ASSESSMENT OF THE MOTHER

The optimal care of the newborn requires knowledge of the family history, prior and current pregnancies, and events of labor and delivery. Neonatal medicine requires a comprehensive understanding of the physiology of normal pregnancy; placental and fetal growth, function, and maturity; and any extrauterine or intrauterine pathologic events that affect the mother, placenta, or fetus. These latter adverse effects may result in an unfavorable neonatal outcome and include such significant maternal influences as poor nutrition, cigarette smoking, poverty, physical or psychological stresses, extremes of age (<16 years, >35 years), race, medical illness present before pregnancy, and medications as well as obstetric complications during the antepartum and intrapartum periods, perinatal infections, exposure to toxins and illicit drugs, and the inherent genetic predisposition of the fetus.

Pregnancies associated with perinatal morbidity or mortality are considered high risk. Identification of high-risk pregnancies is essential to the care of the infant because they may result in intrauterine fetal death, intrauterine growth restriction (IUGR), congenital anomalies, excessive fetal growth, birth asphyxia and trauma, prematurity (birth at <38 weeks) or postmaturity (birth at ≥42 weeks), neonatal disease, or long-term risks of cerebral palsy, mental retardation, and chronic sequelae of neonatal intensive care. Ten percent to 20% of women may be high risk at some time during their pregnancy. Although some obstetric complications are first seen during labor and delivery and cannot be predicted, more than 50% of perinatal mortality and morbidity results from problems identified before delivery as high risk. After a high-risk pregnancy is identified, measures can be instituted to prevent complications, provide intensive fetal surveillance, and initiate appropriate treatments of the mother and fetus.

A history of previous premature birth, intrauterine fetal death, multiple gestation, IUGR, congenital malformation, explained or unexplained neonatal death (e.g., group B streptococcal sepsis), birth trauma, preeclampsia, gestational diabetes, grand multipara status (five or more pregnancies), or cesarean section is associated with additional risk in subsequent pregnancies.

Pregnancy complications that increase the risk of a poor outcome can be secondary to maternal or fetal causes or both. Complications include placenta previa; abruptio placentae; preeclampsia; diabetes; oligohydramnios or polyhydramnios; multiple gestation; blood group sensitization; abnormal levels of unconjugated estriols, chorionic gonadotropin, or alpha-fetoprotein; abnormal fetal ultrasound; hydrops fetalis; maternal trauma or surgery; abnormal fetal presentation (breech); exposure to prescribed or illicit drugs; prolonged labor; cephalopelvic disproportion; prolapsed cord; fetal distress; prolonged or premature rupture of membranes; short cervical length (<25 mm) and the presence of fetal fibronectin in cervical secretions at less than 35 weeks’ gestation (a predictor of preterm labor); cervical infections and vaginosis; and congenital infections, including rubella, cytomegalovirus, herpes simplex, human immunodeficiency virus (HIV), toxoplasmosis, syphilis, and gonorrhea.

Maternal medical complications associated with increased risk of maternal and fetal morbidity and mortality include diabetes, chronic hypertension, congenital heart disease (especially with right-to-left shunting and Eisenmenger complex), glomerulonephritis, collagen vascular disease (especially systemic lupus erythematosus with or without antiphospholipid antibodies), lung disease (cystic fibrosis), severe anemia (sickle cell anemia), hyperthyroidism, myasthenia gravis, idiopathic thrombocytopenic purpura, inborn errors of metabolism (maternal phenylketonuria), and malignancy.

Obstetric complications often are associated with increased fetal or neonatal risk. Vaginal bleeding in the first trimester or early second trimester may be caused by a threatened or actual spontaneous abortion and is associated with increased risk of congenital malformations or chromosomal disorders. Painless vaginal bleeding that is not associated with labor and occurs in the late second or (more likely) third trimester often is the result of placenta previa. Bleeding develops when the placental mass overlies the internal cervical os; this may produce maternal hemorrhagic shock, necessitating transfusions. Bleeding also may result in premature delivery. Painful vaginal bleeding is often the result of retroplacental hemorrhage or placental abruption. Associated findings may be advanced maternal age and parity, maternal chronic hypertension, maternal cocaine use, preterm rupture of membranes, polyhydramnios, twin gestation, and preeclampsia. Fetal asphyxia ensues as the retroplacental hematoma causes placental separation that interferes with fetal oxygenation. Both types of bleeding are associated with fetal blood loss. Neonatal anemia may be more common with placenta previa.

Abnormalities in the volume of amniotic fluid, resulting in oligohydramnios or polyhydramnios, are associated with increased fetal and neonatal risk. Oligohydramnios (amniotic ultrasound fluid index ≤2 cm) is associated with IUGR and major congenital anomalies, particularly of the fetal kidneys, and with chromosomal syndromes. Bilateral renal agenesis results in diminished production of amniotic fluid and a specific deformation syndrome (Potter syndrome), which includes clubfeet, characteristic compressed facies, low-set ears, scaphoid abdomen, and diminished chest wall size accompanied by pulmonary hypoplasia and, often, pneumothorax. Uterine compression in the absence of amniotic fluid retards lung growth, and patients with this condition die of respiratory failure rather than renal insufficiency. Twin-to-twin transfusion syndrome (donor) and complications from amniotic fluid leakage also are associated with oligohydramnios. Oligohydramnios increases the risk of fetal distress during labor (meconium-stained fluid and variable decelerations); the risk may be reduced by saline amnioinfusion during labor.

Polyhydramnios may be acute and associated with premature labor, maternal discomfort, and respiratory compromise. More often, polyhydramnios is chronic and is associated with diabetes, immune or nonimmune hydrops fetalis, multiple gestation, trisomy 18 or 21, and major congenital anomalies. Anencephaly, hydrocephaly, and meningomyelocele are associated with reduced fetal swallowing. Esophageal and duodenal atresia, as well as cleft palate, interfere with swallowing and gastrointestinal fluid dynamics. Additional causes of polyhydramnios include Werdnig-Hoffmann and Beckwith-Wiedemann syndromes, conjoined twins, chylothorax, cystic adenomatoid lung malformation, diaphragmatic hernia, gastroschisis, sacral teratoma, placental chorioangioma, and myotonic dystrophy. Hydrops fetalis may be a result of Rh or other blood group incompatibilities and anemia caused by intrauterine hemolysis of fetal erythrocytes by maternal IgG-sensitized antibodies crossing the placenta. Hydrops is characterized by fetal edema, ascites, hypoalbuminemia, and congestive heart failure. Causes of nonimmune hydrops include fetal arrhythmias (supraventricular tachycardia, congenital heart block), fetal anemia (bone marrow suppression, nonimmune hemolysis, or twin-to-twin transfusion), severe congenital malformation, intrauterine infections, congenital neuroblastoma, inborn errors of metabolism (storage diseases), fetal hepatitis, nephrotic syndrome, and pulmonary lymphangiectasia. Twin-to-twin transfusion syndrome (recipient) also may be associated with polyhydramnios. Polyhydramnios is often the result of unknown causes. If severe, polyhydramnios may be managed with bed rest, indomethacin, or serial amniocenteses.

Premature rupture of the membranes, which occurs in the absence of labor, and prolonged rupture of the membranes (>24 hours) are associated with an increased risk of maternal or fetal infection (chorioamnionitis) and preterm birth. In the immediate newborn period, group B streptococcus and Escherichia coli are the two most common pathogens associated with sepsis. Listeria monocytogenes is a less common cause. Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis, and anaerobic bacteria of the vaginal flora also have been implicated in infection of the amniotic fluid. Infection with community-acquired methicillin-resistant Staphylococcus aureus must be considered for infants with skin infections or with known exposures. The risk of serious fetal infection increases, as the duration between rupture and labor (latent period) increases, especially if the period is greater than 24 hours. Intrapartum antibiotic therapy decreases the risk of neonatal sepsis.

Multiple gestations are associated with increased risk resulting from polyhydramnios, premature birth, IUGR, abnormal presentation (breech), congenital anomalies (intestinal atresia, porencephaly, and single umbilical artery), intrauterine fetal demise, birth asphyxia, and twin-to-twin transfusion syndrome. Twin-to-twin transfusion syndrome is associated with a high mortality and is seen only in monozygotic twins who share a common placenta and have an arteriovenous connection between their circulations. The fetus on the arterial side of the shunt serves as the blood donor, resulting in fetal anemia, growth retardation, and oligohydramnios for this fetus. The recipient, or venous-side twin, is larger or discordant in size, is plethoric and polycythemic, and may show polyhydramnios. Weight differences of 20% and hemoglobin differences of 5 g/dL suggest the diagnosis. Ultrasonography in the second trimester reveals discordant amniotic fluid volume with oliguria/oligohydramnios and hypervolemia/polyuria/polyhydramnios with a distended bladder, with or without hydrops and heart failure. Mortality is high if presentation occurs in the second trimester; however, most monochorionic twins have bidirectional balanced shunts and are not affected. Treatment includes amniocentesis and attempts to ablate the arteriovenous connection (using a laser). The birth order of twins also affects morbidity by increasing the risk of the second-born twin for breech position, birth asphyxia, birth trauma, and respiratory distress syndrome.

Overall, twinning is observed in 1:80 pregnancies; 80% of all twin gestations are dizygotic twins. The diagnosis of the type of twins can be determined by placentation, sex, fetal membrane structure, and, if necessary, tissue and blood group typing or DNA analysis.

Toxemia of pregnancy, or preeclampsia/eclampsia, is a disorder of unknown but probably vascular etiology that may lead to maternal hypertension, uteroplacental insufficiency, IUGR, intrauterine asphyxia, maternal seizures, and maternal death. Toxemia is more common in nulliparous women and in women with twin gestation, chronic hypertension, obesity, renal disease, positive family history of toxemia, or diabetes mellitus. A subcategory of preeclampsia, the HELLP syndrome (hemolysis, elevated liver enzyme levels, low platelets), is more severe and is often associated with a fetal inborn error of fatty acid oxidation (long-chain hydroxyacyl–coenzyme A dehydrogenase of the trifunctional protein complex).

FETUS AND NEWBORN

The late fetal–early neonatal period has the highest mortality rate of any age interval. Perinatal mortality refers to fetal deaths occurring from the 20th week of gestation until the 28th day after birth and is expressed as number of deaths per 1000 live births. Intrauterine fetal death accounts for 40% to 50% of the perinatal mortality rate. Such infants, defined as stillborn, are born without a heart rate and are apneic, limp, pale, and cyanotic. Many stillborn infants exhibit evidence of maceration; pale, peeling skin; corneal opacification; and soft cranial contents.

Mortality rates around the time of birth are expressed as number of deaths per 1000 live births. The neonatal mortality rate includes all infants dying during the period from after birth to the first 28 days of life. Modern neonatal intensive care allows many newborns with life-threatening diseases to survive the neonatal period, only to die of their original diseases or of complications of therapy after 28 days of life. This delayed mortality and mortality caused by acquired illnesses occur during the postneonatal period, which begins after 28 days of life and extends to the end of the first year of life.

The infant mortality rate encompasses the neonatal and the postneonatal periods. In the United States, it declined to 6.7:1000 in 2006. The rate for African-American infants was approximately 13:6000. The most common causes of perinatal and neonatal death are listed in Table 58-1. Overall, congenital anomalies and diseases of the premature infant are the most significant causes of neonatal mortality.

Low birth weight (LBW) infants, defined as infants having birth weights of less than 2500 g, represent a disproportionately large component of the neonatal and infant mortality rates. Although LBW infants make up only about 6% to 7% of all births, they account for more than 70% of neonatal deaths. IUGR is the most common cause of LBW in developing countries, whereas prematurity is the cause in developed countries.

Very low birth weight (VLBW) infants, weighing less than 1500 g at birth, represent about 1% of all births but account for 50% of neonatal deaths. Compared with infants weighing 2500 g or more, LBW infants are 40 times more likely to die in the neonatal period; VLBW infants have a 200-fold higher risk of neonatal death. The LBW rate has not improved in recent years and is one of the major reasons that the U.S. infant mortality rate is high compared with other large, modern, industrialized countries.

Maternal factors associated with a LBW caused by premature birth or IUGR include a previous LBW birth, low socioeconomic status, low level of maternal education, no antenatal care, maternal age younger than 16 years or older than 35 years, short interval between pregnancies, cigarette smoking, alcohol and illicit drug use, physical (excessive standing or walking) or psychological (poor social support) stresses, unmarried status, low prepregnancy weight (<45 kg), poor weight gain during pregnancy (<10 lb), and African-American race. LBW and VLBW rates for African-American women are twice the rates for white women. The neonatal and infant mortality rates are twofold higher among African-American infants. These racial differences are only partly explained by poverty.

In addition to the sociodemographic variables associated with LBW, specific, identifiable medical causes of preterm birth exist. Factors such as uterine anomalies, hydrops fetalis, and most medical illnesses are not seen more frequently in African Americans or in patients of lower socioeconomic status. Prematurity may be caused by spontaneous labor (50% of cases), spontaneous rupture of membranes (25%), or premature delivery for maternal or fetal indications (25%).

ASSESSMENT OF THE FETUS

Fetal size can be determined accurately by ultrasound techniques. Fetal growth can be assessed by determining the fundal height of the uterus through bimanual examination of the gravid abdomen. Ultrasound measurements of the fetal biparietal diameter, femur length, and abdominal circumference are used to estimate fetal growth. A combination of these measurements predicts fetal weight. Deviations from the normal fetal growth curve are associated with high-risk conditions.

IUGR is present when fetal growth stops and, over time, declines to less than the fifth percentile of growth for gestational age or when growth proceeds slowly, but absolute size remains less than the fifth percentile. Growth restriction may result from fetal conditions that reduce the innate growth potential, such as fetal rubella infection, primordial dwarfing syndromes, chromosomal abnormalities, and congenital malformation syndromes. Reduced fetal production of insulin and insulin-like growth factor I is associated with fetal growth restriction. Placental causes of IUGR include villitis (congenital infections), placental tumors, chronic abruptio placentae, twin-to-twin transfusion syndrome, and placental insufficiency. Maternal causes include severe peripheral vascular diseases that reduce uterine blood flow (chronic hypertension, diabetic vasculopathy, and preeclampsia/eclampsia), reduced nutritional intake, alcohol or drug abuse, cigarette smoking, and uterine constraint (noted predominantly in mothers of small stature with a low prepregnancy weight) and reduced weight gain during pregnancy. The outcome of IUGR depends on the cause of the reduced fetal growth and the associated complications after birth (Table 58-2). Fetuses subjected to chronic intrauterine hypoxia as a result of uteroplacental insufficiency are at an increased risk for the comorbidities of birth asphyxia, polycythemia, and hypoglycemia. Fetuses with reduced tissue mass due to chromosomal, metabolic, or multiple congenital anomaly syndromes have poor outcomes based on the prognosis for the particular syndrome. Fetuses born to small mothers and fetuses with poor nutritional intake usually show catch-up growth after birth.

TABLE 58-2 Problems of Intrauterine Growth Restriction and Small for Gestational Age

* Other problems are common to the gestational age–related risks of prematurity if born before 37 weeks.

Modified from Stoll BJ, Kliegman RM: The high-risk infant. In Behrman RE, Kliegman RM, Jenson HB, editors: Nelson Textbook of Pediatrics, 16th ed, Philadelphia, 2000, Saunders.

Fetal size does not always correlate with functional or structural maturity. Determining fetal maturity is crucial when making a decision to deliver a fetus because of fetal or maternal disease. Fetal gestational age may be determined accurately on the basis of a correct estimate of the last menstrual period. Clinically relevant landmark dates can be used to determine gestational age; the first audible heart tones by fetoscope are detected at 18 to 20 weeks (12 to 14 weeks by Doppler methods), and quickening of fetal movements usually is perceived at 18 to 20 weeks. However, it is not always possible to determine fetal maturity by such dating, especially in a high-risk situation, such as preterm labor or a diabetic pregnancy.

Surfactant, a combination of surface-active phospholipids and proteins, is produced by the maturing fetal lung and eventually is secreted into the amniotic fluid. The amount of surfactant in amniotic fluid is a direct reflection of surface-active material in the fetal lung and can be used to predict the presence or absence of pulmonary maturity. Because phosphatidylcholine, or lecithin, is a principal component of surfactant, the determination of lecithin in amniotic fluid is used to predict a mature fetus. Lecithin concentration increases with increasing gestational age, beginning at 32 to 34 weeks.

Methods used to assess fetal well-being before the onset of labor are focused on identifying a fetus at risk for asphyxia or a fetus who already is compromised by uteroplacental insufficiency. The oxytocin challenge test simulates uterine contractions through an infusion of oxytocin sufficient to produce three contractions in a 10-minute period. The development of periodic fetal bradycardia out of phase with uterine contractions (late deceleration) is a positive test result and predicts an at-risk fetus.

The nonstress test examines the heart rate response to fetal body movements. Heart rate increases of more than 15 beats/min, lasting 15 seconds, are reassuring. If two such episodes occur in 30 minutes, the test result is considered reactive (versus nonreactive), and the fetus is not at risk. Additional signs of fetal well-being are fetal breathing movements, gross body movements, fetal tone, and the presence of amniotic fluid pockets of greater than 2 cm, detected by ultrasound. The biophysical profile combines the nonstress test with these four parameters and offers the most accurate fetal assessment.

Doppler examination of the fetal aorta or umbilical arteries permits identification of decreased or reversed diastolic blood flow associated with increased peripheral vascular resistance, fetal hypoxia with acidosis, and placental insufficiency. Cordocentesis (percutaneous umbilical blood sampling) can provide fetal blood for PO₂, pH, lactate, and hemoglobin measurements to identify a hypoxic, acidotic, or anemic fetus who is at risk for intrauterine fetal demise or birth asphyxia. Cordocentesis also can be used to determine fetal blood type, platelet count, microbial culture, antibody titer, and rapid karyotype.

In a high-risk pregnancy, the fetal heart rate should be monitored continuously during labor, as should uterine contractions. Fetal heart rate abnormalities may indicate baseline tachycardia (>160 beats/min as a result of anemia, β-sympathomimetic drugs, maternal fever, hyperthyroidism, arrhythmia, or fetal distress), baseline bradycardia (<120 beats/min as a result of fetal distress, complete heart block, or local anesthetics), or reduced beat-to-beat variability (flattened tracing resulting from fetal sleep, tachycardia, atropine, sedatives, prematurity, or fetal distress). Periodic changes of the heart rate relative to uterine pressure help determine the presence of hypoxia and acidosis caused by uteroplacental insufficiency or maternal hypotension (late or type II decelerations) or by umbilical cord compression (variable decelerations). In the presence of severe decelerations (late or repeated prolonged variable), a fetal scalp blood gas level should be obtained to assess fetal acidosis. A scalp pH of less than 7.20 indicates fetal hypoxic compromise. A pH between 7.20 and 7.25 is in a borderline zone and warrants repeat testing.

Fetal anomalies may be detected by ultrasonography. Emphasis should be placed on visualization of the genitourinary tract; the head (for anencephaly or hydrocephaly), neck (for thickened nuchal translucency), and back (for spina bifida); skeleton; gastrointestinal tract; and heart. Four-chamber and great artery views are required for detection of heart anomalies. Chromosomal anomaly syndromes may reveal choroid cysts, hypoplasia of the middle phalanx of the fifth digit, nuchal fluid, retrognathism, and low-set ears. In addition, chromosomal syndromes often are associated with an abnormal “triple test” (low estriols, low maternal serum alpha-fetoprotein levels, and elevated placental chorionic gonadotropin levels). If a fetal abnormality is detected, fetal therapy or delivery with therapy in the neonatal intensive care unit may be lifesaving.

ASSESSMENT OF THE NEWBORN

The approach to the birth of an infant requires a detailed history (Table 58-3). Knowing the mother’s risk factors enables the delivery room team to anticipate problems that may occur after birth. The history of a woman’s labor and delivery can reveal events that might lead to complications affecting either the mother or the neonate, even when the pregnancy was previously considered low risk. Anticipating the need to resuscitate a newborn as a result of fetal distress increases the likelihood of successful resuscitation.

The transition from fetal to neonatal physiology occurs at birth. Oxygen transport across the placenta results in a gradient between the maternal and fetal PaO₂. Although fetal oxygenated blood has a low PaO₂ level compared with that of adults and infants, the fetus is not anaerobic. Fetal oxygen uptake and consumption are similar to neonatal rates, even though the thermal environments and activity levels of fetuses and neonates differ. The oxygen content of fetal blood is almost equal to the oxygen content in older infants and children because fetal blood has a much higher concentration of hemoglobin.

Fetal hemoglobin (two alpha and two gamma chains) has a higher affinity for oxygen than adult hemoglobin, facilitating oxygen transfer across the placenta. The fetal hemoglobin-oxygen dissociation curve is shifted to the left of the adult curve (Fig. 58-1); at the same PaO₂ level, fetal hemoglobin is more saturated than adult hemoglobin. Because fetal hemoglobin functions on the steep, lower end of the oxygen saturation curve (PaO₂, 20 to 30 mm Hg), however, oxygen unloading to the tissue is not deficient. In contrast, at the higher oxygen concentrations present in the placenta, oxygen loading is enhanced. In the last trimester, fetal hemoglobin production begins to decrease as adult hemoglobin production begins to increase, becoming the only hemoglobin available to the infant by 3 to 6 months of life. At this time, the fetal hemoglobin dissociation curve has shifted to the adult position.

FIGURE 58-1 Hemoglobin-oxygen dissociation curves. The position of the adult curve depends on the binding of adult hemoglobin to 2,3-diphosphoglycerate (DPG), temperature, PCO₂, and hydrogen ion concentration (pH).

A portion of well-oxygenated umbilical venous blood returning to the heart from the placenta perfuses the liver. The remainder bypasses the liver through a shunt (the ductus venosus) and enters the inferior vena cava. This oxygenated blood in the vena cava constitutes 65% to 70% of venous return to the right atrium. The crista dividens in the right atrium directs one third of this blood across the patent foramen ovale to the left atrium, where it subsequently is pumped to the coronary, cerebral, and upper extremity circulations by the left ventricle. Venous return from the upper body combines with the remaining two thirds of the vena caval blood in the right atrium and is directed to the right ventricle. This mixture of venous low-oxygenated blood from the upper and lower body enters the pulmonary artery. Only 8% to 10% of it is pumped to the pulmonary circuit; the remaining 80% to 92% of the right ventricular output bypasses the lungs through a patent ductus arteriosus and enters the descending aorta. The amount of blood flowing to the pulmonary system is low because vasoconstriction produced by medial muscle hypertrophy of the pulmonary arterioles and fluid in the fetal lung increases resistance to blood flow. Pulmonary artery tone also responds to hypoxia, hypercapnia, and acidosis with vasoconstriction, a response that may increase pulmonary vascular resistance further. The ductus arteriosus remains patent in the fetus because of low PaO₂ levels and dilating prostaglandins. In utero, the right ventricle is the dominant ventricle, pumping 65% of the combined ventricular output, which is a high volume (450 mL/kg/min) compared with that pumped by an older infant’s right ventricle (200 mL/kg/min).

The transition of the circulation occurring between the fetal and neonatal periods involves the removal of the low-resistance circulation of the placenta, the onset of breathing, reduction of pulmonary arterial resistance, and closure of in utero shunts. Clamping the umbilical cord eliminates the low-pressure system of the placenta and increases systemic blood pressure. Decreased venous return from the placenta decreases right atrial pressure. As breathing begins, air replaces lung fluid, maintaining the functional residual capacity. Fluid leaves the lung, in part, through the trachea; it is either swallowed or squeezed out during vaginal delivery. The pulmonary lymphatic and venous systems reabsorb the remaining fluid.

Most normal infants require little pressure to spontaneously open the lungs after birth (5 to 10 cm H₂O). A few infants require assistance with greater opening pressures (20 to 30 cm H₂O). With the onset of breathing, pulmonary vascular resistance decreases, partly a result of the mechanics of breathing and partly a result of the elevated arterial oxygen tensions. The increased blood flow to the lungs increases the volume of pulmonary venous blood returning to the left atrium; left atrial pressure now exceeds right atrial pressure, and the foramen ovale closes. As the flow through the pulmonary circulation increases and arterial oxygen tensions rise, the ductus arteriosus begins to constrict. In a term infant, this constriction functionally closes the ductus arteriosus within 1 day after birth. A permanent closure requires thrombosis and fibrosis, a process that may take several weeks. In a premature infant, the ductus arteriosus is less sensitive to the effects of oxygen; if circulating levels of vasodilating prostaglandins are elevated, the ductus arteriosus may remain patent. This patency is a common problem in a premature infant with respiratory distress syndrome.

Ventilation, oxygenation, and normal pH and PCO₂ levels immediately reduce pulmonary artery vasoconstriction by causing smooth muscle relaxation. Remodeling of the medial muscle hypertrophy begins at birth and continues for the next 3 months, resulting in a further reduction of pulmonary vascular resistance and a further increase of pulmonary blood flow. Persistence or aggravation of pulmonary vasoconstriction caused by acidosis, hypoxia, hypercapnia, hypothermia, polycythemia, asphyxia, shunting of blood from the lungs, or pulmonary parenchymal hypoplasia results in persistent pulmonary hypertension of the newborn (PPHN). Failure to replace pulmonary alveolar fluid completely with air can lead to respiratory distress (transient tachypnea of the newborn).

Routine Delivery Room Care and Resuscitation

Silver nitrate (1%) instilled into both eyes without being washed out is an indicated effective therapy for the prevention of neonatal gonococcal ophthalmia, which can result in severe panophthalmitis and subsequent blindness. Silver nitrate may produce a chemical conjunctivitis with a mucopurulent discharge and is not effective against C. trachomatis. Many hospitals use erythromycin drops to prevent neonatal gonococcal and chlamydial eye disease.

Bacterial colonization of a newborn may begin in utero if the fetal membranes have been ruptured. Most infants undergo colonization after birth and acquire the bacteria present in the mother’s genitourinary system, such as group B streptococci, staphylococci, E. coli, and clostridia. Colonization is common at the umbilicus, skin, nasopharynx, and intestine. Antiseptic skin or cord care is routine in most nurseries to prevent the spread of pathologic bacteria from one infant to another and to prevent disease in the individual infant. Staphylococcal bullous impetigo, omphalitis, diarrhea, and systemic disease may result from colonization with virulent S. aureus. For term infants, washing of the skin with 3% hexachlorophene is not routinely recommended but may prevent serious staphylococcal disease; preterm infants may absorb hexachlorophene, and neurotoxicity may develop. Triple antibiotic ointment (polymyxin B, neomycin, and bacitracin) or bacitracin may be applied to the umbilical cord to reduce its colonization with gram-positive bacteria. Epidemics of S. aureus nursery infections are managed with strict infectious disease control measures (cohorting, hand washing, and monitoring for colonization).

Vitamin K prophylaxis (intramuscular) should be given to all infants to prevent hemorrhagic disease of the newborn. Before discharge, infants should receive the hepatitis B vaccine and be screened for various diseases (Tables 58-4 and 58-5).

TABLE 58-4 Approximate Frequencies of Disorders Included in or Considered for Newborn Screening in the United States

TABLE 58-5 Abnormal Newborn Screening Results: Possible Implications and Initial Action to Be Taken

Newborn Screening Finding	Differential Diagnosis	Initial Action
↑ Phenylalanine	PKU, non-PKU hyperphenylalaninemia, pterin defect, galactosemia, transient hyperphenylalaninemia	Repeat blood specimen
↓ T4, ↑ TSH	Congenital hypothyroidism, iodine exposure	Repeat blood specimen or thyroid function testing, begin thyroxine treatment
↓ T4, normal TSH	Maternal hyperthyroidism, thyroxine-binding globulin deficiency, secondary hypothyroidism, congenital hypothyroidism with delayed TSH elevation	Repeat blood specimen
↑ Galactose (1-P) transferase	Galactosemia, liver disease, reducing substance, repeat deficiency variant (Duarte), transient	Clinical evaluation, urine for blood specimen. If reducing substance positive, begin lactose-free formula
↓ Galactose-1-phosphate uridyltransferase	Galactosemia, transferase deficiency variant (Duarte), transient	Clinical evaluation, urine for reducing substance, repeat blood specimen. If reducing substance positive, begin lactose-free formula
↑ Methionine	Homocystinuria, isolated liver dysfunction, tyrosinemia type I, transient hypermethioninemia	Repeat blood and urine specimen
↑ Leucine	Maple syrup urine disease, transient elevation	Clinical evaluation including urine for ketones, acid-base status, amino acid studies, immediate neonatal ICU care if urine ketones positive
↑ Tyrosine	Tyrosinemia type I or type II, transient tyrosinemia, liver disease	Repeat blood specimen
↑ 17α-Hydroxyprogesterone	Congenital adrenal hyperplasia, prematurity, transient (residual fetal adrenal cortex), stress in neonatal period, early specimen collection	Clinical evaluation including genital examination, serum electrolytes, repeat blood specimen
S-hemoglobin	Sickle cell disease, sickle cell trait	Hemoglobin electrophoresis
↑ Trypsinogen	Cystic fibrosis, transient, intestinal anomalies, perinatal stress, trisomies 13 and 18, renal failure	Repeat blood specimen, possible sweat test and DNA testing
↑ Creatinine phosphokinase	Duchenne muscular dystrophy, other type of muscular dystrophy, birth trauma, invasive procedure	Repeat blood test
↓ Biotinidase	Biotinidase deficiency	Serum biotinidase assay, biotin therapy
↓ G6PD	G6PD deficiency	Complete blood count, bilirubin determination
↓ α1-Antitrypsin	α1-Antitrypsin deficiency	Confirmatory test
Toxoplasma antibody (IgM)	Congenital toxoplasmosis	Infectious disease consultation
HIV antibody (IgG)	Maternally transmitted HIV, possible AIDS	Infectious disease consultation
↑ Organic acids	Fatty acid oxidation defects (medium-chain acyl-CoA dehydrogenase deficiency)	Perform specific assay (tandem mass spectroscopy); frequent feeds

G6PD, glucose-6-phosphate dehydrogenase; ICU, intensive care unit; PKU, phenylketonuria; T₄, thyroxine; TSH, thyroid-stimulating hormone.

From Kim SZ, Levy HL: Newborn screening. In Taeusch HW, Ballard RA, editors: Avery’s Diseases of the Newborn, 7th ed, Philadelphia, 1998, Saunders.

Fetal or neonatal hypoxia, hypercapnia, poor cardiac output, and a metabolic acidosis can result from numerous conditions affecting the fetus, the placenta, or the mother. Whether in utero or after birth, asphyxia-caused hypoxic-ischemic brain injury is the result of reduced gaseous exchange through the placenta or through the lungs. Asphyxia associated with severe bradycardia or cardiac insufficiency reduces or eliminates tissue blood flow, resulting in ischemia. The fetal and neonatal circulatory systems respond to reduced oxygen availability by shunting the blood preferentially to the brain, heart, and adrenal glands and away from the intestine, kidneys, lungs, and skin.

Metabolic acidosis during asphyxia is caused by the combined effects of poor cardiac output secondary to hypoxic depression of myocardial function, systemic hypoxia, and tissue anaerobic metabolism. With severe or prolonged intrauterine or neonatal asphyxia, multiple vital organs are affected (Table 58-6).

TABLE 58-6 Effects of Asphyxia

System	Effect
Central nervous system	Hypoxic-ischemic encephalopathy, IVH, PVL, cerebral edema, seizures, hypotonia, hypertonia
Cardiovascular	Myocardial ischemia, poor contractility, tricuspid insufficiency, hypotension
Pulmonary	Persistent pulmonary hypertension, respiratory distress syndrome
Renal	Acute tubular or cortical necrosis
Adrenal	Adrenal hemorrhage
Gastrointestinal	Perforation, ulceration, necrosis
Metabolic	Inappropriate ADH, hyponatremia, hypoglycemia, hypocalcemia, myoglobinuria
Integument	Subcutaneous fat necrosis
Hematology	Disseminated intravascular coagulation

ADH, antidiuretic hormone; IVH, intraventricular hemorrhage; PVL, periventricular leukomalacia.

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Many conditions that contribute to fetal or neonatal asphyxia are the same medical or obstetric problems associated with high-risk pregnancy (Table 58-7). Maternal diseases that interfere with uteroplacental perfusion (chronic hypertension, preeclampsia, and diabetes mellitus) place the fetus at risk for intrauterine asphyxia. Maternal epidural anesthesia and the development of the vena caval compression syndrome may produce maternal hypotension, which decreases uterine perfusion. Maternal medications given to relieve pain during labor may cross the placenta and depress the infant’s respiratory center, resulting in apnea at the time of birth.

TABLE 58-7 Etiology of Birth Asphyxia

Type	Example
INTRAUTERINE
Hypoxia-ischemia	Uteroplacental insufficiency, abruptio placentae, prolapsed cord, maternal hypotension, unknown
Anemia-shock	Vasa previa, placenta previa, fetomaternal hemorrhage, erythroblastosis
INTRAPARTUM
Birth trauma	Cephalopelvic disproportion, shoulder dystocia, breech presentation, spinal cord transection
Hypoxia-ischemia	Umbilical cord compression, tetanic contraction, abruptio placentae
POSTPARTUM
Central nervous system	Maternal medication, trauma, previous episodes of fetal hypoxia–acidosis
Congenital neuromuscular disease	Congenital myasthenia gravis, myopathy, myotonic dystrophy
Infection	Consolidated pneumonia, shock
Airway disorder	Choanal atresia, severe obstructing goiter, laryngeal webs
Pulmonary disorder	Severe immaturity, pneumothorax, pleural effusion, diaphragmatic hernia, pulmonary hypoplasia
Renal disorder	Pulmonary hypoplasia, pneumothorax

Fetal conditions associated with asphyxia usually do not become manifested until delivery, when the infant must initiate and sustain ventilation. In addition, the upper and lower airways must be patent and unobstructed. Alveoli must be free from foreign material, such as meconium, amniotic fluid debris, and infectious exudates, which increases airway resistance, reduces lung compliance, and leads to respiratory distress and hypoxia. Some extremely immature infants weighing less than 1000 g at birth may be unable to expand their lungs, even in the absence of other pathology. Their compliant chest walls and surfactant deficiency may result in poor air exchange, retractions, hypoxia, and apnea.

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The newborn (particularly a preterm infant) responds paradoxically to hypoxia with apnea rather than tachypnea as occurs in adults. Episodes of intrauterine asphyxia also may depress the neonatal central nervous system. If recovery of the fetal heart rate occurs as a result of improved uteroplacental perfusion, fetal hypoxia and acidosis may resolve. Nonetheless, if the effect on the respiratory center is more severe, a newborn may not initiate an adequate ventilatory response at birth and may undergo another episode of asphyxia.

The Apgar examination, a rapid scoring system based on physiologic responses to the birth process, is a good method for assessing the need to resuscitate a newborn (Table 58-8). At intervals of 1 minute and 5 minutes after birth, each of the five physiologic parameters is observed or elicited by a qualified examiner. Full-term infants with a normal cardiopulmonary adaptation should score 8 to 9 at 1 and 5 minutes. Apgar scores of 4 to 7 warrant close attention to determine whether the infant’s status will improve and to ascertain whether any pathologic condition is contributing to the low Apgar score.

TABLE 58-8 Apgar Score

By definition, an Apgar score of 0 to 3 represents either a cardiopulmonary arrest or a condition caused by severe bradycardia, hypoventilation, or central nervous system depression. Most low Apgar scores are caused by difficulty in establishing adequate ventilation and not by primary cardiac pathology. In addition to an Apgar score of 0 to 3, most infants with asphyxia severe enough to cause neurologic injury also manifest fetal acidosis (pH <7); seizures, coma, or hypotonia; and multiorgan dysfunction. Low Apgar scores may be caused by fetal hypoxia or other factors listed in Table 58-7. Most infants with low Apgar scores respond to assisted ventilation by face mask or by endotracheal intubation and usually do not need emergency medication.

Resuscitation of a newborn with a low Apgar score follows the same systematic sequence as that for resuscitation of older patients, but in the newborn period this simplified ABCD approach requires some qualification (Fig. 58-2). In the ABCD approach, A stands for securing a patent airway by clearing amniotic fluid or meconium by suctioning; A is also a reminder of anticipation and the need for knowing the events of pregnancy, labor, and delivery. Evidence of a diaphragmatic hernia and a low Apgar score indicate that immediate endotracheal intubation is required. If a mask and bag are used, gas enters the lung and the stomach, and the latter may act as an expanding mass in the chest that compromises respiration. If fetal hydrops has occurred with pleural effusions, a bilateral thoracentesis to evacuate the pleural effusions may be needed to establish adequate ventilation.

FIGURE 58-2 Algorithm for resuscitation of the newborn infant. HR, heart rate.

(From National guidelines for neonatal resuscitation. Pediatrics 106:E29, 2000.)

B represents breathing. If the neonate is apneic or hypoventilates and remains cyanotic, artificial ventilation should be initiated. Ventilation should be performed with a well-fitted mask attached to an anesthesia bag and a manometer to prevent extremely high pressures from being given to the newborn; 100% oxygen should be administered through the mask. If the infant does not revive, an endotracheal tube should be placed, attached to the anesthesia bag and manometer, and 100% oxygen should be administered. The pressure generated should begin at 20 to 25 cm H₂O, with a rate of 40 to 60 breaths/min. An adequate response to ventilation includes good chest rise, return of breath sounds, well-oxygenated color, heart rate returning to the normal range (120 to 160 beats/min), normal end-tidal carbon dioxide, and, later, increased muscle activity and wakefulness. The usual recovery after a cardiac arrest first involves a return to a normal heart rate followed by disappearance of cyanosis, and noticeably improved perfusion. An infant may remain limp and be apneic for a prolonged time after return of cardiac output and correction of acidosis.

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Breathing initially should be briefly delayed if meconium-stained amniotic fluid is present to avoid dissemination of meconium into the lungs, producing severe aspiration pneumonia. If meconium is noted in the amniotic fluid, the oropharynx should be suctioned when the head is delivered. After the birth of a depressed infant, the oral cavity should be suctioned again; the vocal cords should be visualized and the infant intubated, with suction applied while the tube is below the vocal cords. If meconium is noted below the cords, intubation should be repeated quickly to clear the remaining meconium. During this time, the infant should not be stimulated to breathe, and positive-pressure ventilation should not be applied.

C represents circulation and external cardiac massage. If artificial ventilation does not improve bradycardia, if asystole is present, or if peripheral pulses cannot be palpated, external cardiac massage should be performed at a rate of 120 compressions/min with compressions and breaths given at a ratio of 3:1. External cardiac massage usually is not needed because most infants in the delivery room respond to ventilation.

D represents the administration of drugs. If bradycardia is unresponsive to ventilation or if asystole is present, resuscitation drugs should be administered. Intravenous (IV) epinephrine (1:10,000), 0.1 to 0.3 mL/kg, should be given through an umbilical venous line or injected into the endotracheal tube. Additional medications for resuscitation include 2 mEq/kg of IV sodium bicarbonate if acidosis is prolonged and a rapid infusion of fluids (normal saline, or O-negative red blood cells if anemia is present) if poor perfusion suggests hypovolemia. Sodium bicarbonate should be given only if severe metabolic acidosis is suspected or is proven by blood gas analysis. Sodium bicarbonate should not be given unless the lungs are adequately ventilated. Before medications are administered in the presence of electrical cardiac activity with poor pulses, it is important to determine whether there is a pneumothorax. Transillumination of the thorax, involving the use of a bright light through each side of the thorax and over the sternum, may suggest pneumothorax if one side transmits more light than the other. Breath sounds may be decreased over a pneumothorax and there may be a shift of the heart tones away from the side of a tension pneumothorax.

If central nervous system depression in the infant may be due to a narcotic medication given to the mother, 0.1 mg/kg of naloxone (Narcan) can be given to the infant intravenously or endotracheally. Before this drug is administered, the ABCs should be followed carefully. Naloxone should not be given to a newborn of a mother who is suspected of being addicted to narcotics or is on methadone maintenance because the newborn may experience severe withdrawal seizures.

Physical Examination and Gestational Age Assessment

The first physical examination of a newborn may be a general physical examination of a well infant, an examination to confirm fetal diagnoses or to determine the cause of various manifestations of neonatal diseases. Problems in the transition from fetal to neonatal life may be detectable immediately in the delivery room or during the first day of life. Physical examination also may reveal effects of the labor and delivery resulting from asphyxia, drugs, or birth trauma. The first newborn examination is an important way to detect congenital malformations or deformations (Table 58-9). Significant congenital malformations may be present in 1% to 3% of all births.

TABLE 58-9 Life-Threatening Congenital Anomalies

Name	Manifestations
Choanal atresia (stenosis)	Respiratory distress in delivery room, apnea, unable to pass nasogastric tube through nares
Pierre Robin syndrome	Micrognathia, cleft palate, airway obstruction
Diaphragmatic hernia	Scaphoid abdomen, bowel sounds present in left chest, heart shifted to right, respiratory distress, polyhydramnios
Tracheoesophageal fistula	Polyhydramnios, aspiration pneumonia, excessive salivation, unable to place nasogastric tube in stomach
Intestinal obstruction: volvulus, duodenal atresia, ileal atresia	Polyhydramnios, bile-stained emesis, abdominal distention
Gastroschisis/omphalocele	Polyhydramnios; intestinal obstruction
Renal agenesis/Potter syndrome	Oligohydramnios, anuria, pulmonary hypoplasia, pneumothorax
Hydronephrosis	Bilateral abdominal masses
Neural tube defects: anencephalus, meningomyelocele	Polyhydramnios, elevated α-fetoprotein; decreased fetal activity
Down syndrome (trisomy 21)	Hypotonia, congenital heart disease, duodenal atresia
Ductal-dependent congenital heart disease	Cyanosis, murmur, shock

Appearance

The general appearance of the infant should be evaluated first. Signs such as cyanosis, nasal flaring, intercostal retractions, and grunting suggest pulmonary disease. Meconium staining of the umbilical cord, nails, and skin suggest fetal distress and the possibility of aspiration pneumonia. The level of spontaneous activity, passive muscle tone, quality of the cry, and apnea are useful screening signs to evaluate the state of the nervous system.

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Vital Signs

The examination should proceed with an assessment of vital signs, particularly heart rate (normal rate, 120 to 160 beats/min); respiratory rate (normal rate, 30 to 60 breaths/min); temperature (usually done per rectum and later as an axillary measurement); and blood pressure (often reserved for sick infants). Length, weight, and head circumference should be measured and plotted on growth curves to determine whether growth is normal, accelerated, or retarded for the specific gestational age.

Gestational Age

Gestational age is determined by an assessment of various physical signs (Fig. 58-3) and neuromuscular characteristics (Fig. 58-4) that vary according to fetal age and maturity. Physical criteria mature with advancing fetal age, including increasing firmness of the pinna of the ear; increasing size of the breast tissue; decreasing fine, immature lanugo hair over the back; and decreasing opacity of the skin. Neurologic criteria mature with gestational age, including increasing flexion of the legs, hips, and arms; increasing tone of the flexor muscles of the neck; and decreasing laxity of the joints. These signs are determined during the first day of life and are assigned scores. The cumulative score is correlated with a gestational age, which is usually accurate to within 2 weeks (Fig. 58-5).

FIGURE 58-3 Physical criteria for assessment of maturity and gestational age. Expanded New Ballard Score (NBS) includes extremely premature infants and has been refined to improve accuracy in more mature infants.

(From Ballard JL, et al: New Ballard Score, expanded to include extremely premature infants. J Pediatr 119:417, 1991.)

FIGURE 58-4 Neuromuscular criteria for assessment of maturity and gestational age. Expanded New Ballard Score (NBS) includes extremely premature infants and has been refined to improve accuracy in more mature infants.

(From Ballard JL, et al: New Ballard Score, expanded to include extremely premature infants. J Pediatr 119:417, 1991).

FIGURE 58-5 Maturity rating as calculated by adding the physical and neurologic scores, calculating the gestational age.

(From Ballard JL, et al: New Ballard Score, expanded to include extremely premature infants. J Pediatr 119:417, 1991).

Gestational age assessment permits the detection of abnormal fetal growth patterns, aiding in predicting the neonatal complications of largeness or smallness for gestational age (Fig. 58-6). Infants born at a weight greater than the 90th percentile for age are considered large for gestational age. Among the risks associated with being large for gestational age are all the risks of the infant of a diabetic mother and risks associated with postmaturity. Infants born at a weight less than 10th percentile for age (some growth curves use <2 standard deviations or the fifth percentile) are small for gestational age and have IUGR. Problems associated with small for gestational age infants include congenital malformations, in addition to the problems listed in Table 58-2.

FIGURE 58-6 Birth weight–specific and estimated gestational age–specific mortality rates. The dashed lines of the figure represent the 10th and 90th percentile weights. The grid lines are plotted by each gestational age and in 250-g weight increments. Each number in the box is the percent mortality rate for the grid defined by gestational age and birth weight range.

(From Thomas P, Peabody J, Turnier V, et al: A new look at intrauterine growth and impact of race, attitude, and gender. Pediatrics 106:E21, 2000.)

Skin

The skin should be evaluated for pallor, plethora, jaundice, cyanosis, meconium staining, petechiae, ecchymoses, congenital nevi, and neonatal rashes. Vasomotor instability with cutis marmorata, telangiectasia, phlebectasia (intermittent mottling with venous prominence), and acrocyanosis (feet and hands) is normal in a premature infant. Acrocyanosis also may be noted in a healthy term infant in the first days after birth. The harlequin color change is a striking, transient, but normal sign of vasomotor instability and divides the body from head to pubis, through the midline, into equal halves of pink and pale color.

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The skin is covered with lanugo hair, which disappears by term gestation. Hair tufts over the lumbosacral spine suggest a spinal cord defect. Vernix caseosa, a soft, white, creamy layer covering the skin in preterm infants, disappears by term. Post-term infants often have peeling, parchment-like skin. Mongolian spots are transient, dark blue to black pigmented macules seen over the lower back and buttocks in 90% of African-American, Indian, and Asian infants. Nevus simplex (salmon patch), or pink macular hemangiomas, is common, usually transient, and noted on the back of the neck, eyelids, and forehead. Nevus flammeus, or port-wine stain, is seen on the face and should cause the examiner to consider Sturge-Weber syndrome (trigeminal angiomatosis, convulsions, and ipsilateral intracranial tram-line calcifications).

Congenital melanocytic nevi are pigmented lesions of varying size noted in 1% of neonates. Giant pigmented nevi are uncommon but have malignant potential. Capillary hemangiomas are raised, red lesions, whereas cavernous hemangiomas are deeper, blue masses. Both lesions increase in size after birth, then resolve when the child is 1 to 4 years of age. When enlarged, these hemangiomas may produce high-output heart failure or platelet trapping and hemorrhage. Erythema toxicum is an erythematous, papular-vesicular rash common in neonates that develops after birth and involves eosinophils in the vesicular fluid. Pustular melanosis, more common in African-American infants, may be seen at birth and consists of a small, dry vesicle on a pigmented brown macular base. Erythema toxicum and pustular melanosis are benign lesions, but may mimic more serious conditions, such as the vesicular rash of disseminated herpes simplex or the bullous eruption of S. aureus impetigo. Tzanck smear, Gram stain, Wright stain, direct fluorescent antibody stain, polymerase chain reaction for herpes DNA, and appropriate cultures may be needed to distinguish these rashes. Other common characteristic rashes are milia (yellow-white epidermal cysts of the pilosebaceous follicles that are noted on the nose) and miliaria (prickly heat), which is caused by obstructed sweat glands. Edema may be present in preterm infants, but also suggests hydrops fetalis, sepsis, hypoalbuminemia, or lymphatic disorders.

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Skull

The skull may be elongated and molded after a prolonged labor, which resolves 2 to 3 days after birth. The sutures should be palpated to determine the width and the presence of premature fusion or cranial synostosis. The anterior and posterior fontanelles should be soft and nonbulging, with the anterior larger than the posterior. A large fontanelle is associated with hydrocephalus, hypothyroidism, rickets, and other disorders. Soft areas away from the fontanelle are craniotabes; these lesions feel like a ping-pong ball when they are palpated. They may be a result of in utero compression. The skull should be examined carefully for signs of trauma or lacerations from internal fetal electrode sites or fetal scalp pH sampling; abscess formation may develop in these areas.

Face, Eyes, and Mouth

The face should be inspected for dysmorphic features, such as epicanthal folds, hypertelorism, preauricular tags or sinuses, low-set ears, long philtrum, and cleft lip or palate. Facial asymmetry may be a result of seventh nerve palsy; head tilt may be caused by torticollis.

The eyes should open spontaneously, especially in an upright position. Before 28 weeks’ gestational age, the eyelids may be fused. Coloboma, megalocornea, and microphthalmia suggest other malformations or intrauterine infections. A cloudy cornea greater than 1 cm in diameter also may be seen in congenital glaucoma, uveal tract dysgenesis, and storage diseases. Conjunctival and retinal hemorrhages are common and usually of no significance. The pupillary response to light is present at 28 weeks of gestation. The red reflex of the retina is shown easily. A white reflex, or leukokoria, is abnormal and may be the result of cataracts, ocular tumor, severe chorioretinitis, persistent hyperplastic primary vitreous, or retinopathy of prematurity.

The mouth should be inspected for the presence of natal teeth, clefts of the soft and hard palate and uvula, and micrognathia. A bifid uvula suggests a submucosal cleft. White, shiny, multiple transient epidermal inclusion cysts (Epstein pearls) on the hard palate are normal. Hard, marble-sized masses in the buccal mucosa are usually transient idiopathic fat necrosis. The tympanic membranes are dull, gray, opaque, and immobile in the first 1 to 4 weeks. These findings should not be confused with otitis media.

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Neck and Chest

The neck appears short and symmetrical. Abnormalities include midline clefts or masses caused by thyroglossal duct cysts or by goiter and lateral neck masses (or sinuses), which are the result of branchial clefts. Cystic hygromas and hemangiomas may be present. Shortening of the sternocleidomastoid muscle with a fibrous tumor over the muscle produces head tilt and asymmetrical facies (neonatal torticollis). Arnold-Chiari malformation and cervical spine lesions also produce torticollis. Edema and webbing of the neck suggest Turner syndrome. Both clavicles should be palpated for fractures.

Examination of the chest includes inspection of the chest wall to identify asymmetry resulting from absence of the pectoralis muscle and inspection of the breast tissue to determine gestational age and detect a breast abscess. Boys and girls may have breast engorgement and produce milk; milk expression should not be attempted. Supernumerary nipples may be bilateral and may be associated with renal anomalies.

Lungs

Examination of the lungs includes observations of the rate, depth, and nature of intercostal or sternal retractions. Breath sounds should be equal on both sides of the chest, and rales should not be heard after the first 1 to 2 hours of life. Diminished or absent breath sounds on one side suggest pneumothorax, collapsed lung, pleural effusion, or diaphragmatic hernia. Shift of the cardiac impulse away from a tension pneumothorax and diaphragmatic hernia and toward the collapsed lung is a helpful physical finding for differentiating these disorders. Subcutaneous emphysema of the neck or chest also suggests a pneumothorax or pneumomediastinum, whereas bowel sounds auscultated in the chest in the presence of a scaphoid abdomen suggest a diaphragmatic hernia.

Heart

The position of the heart in infants is more midline than in older children. The first heart sound is normal, whereas the second heart sound may not be split in the first day of life. Decreased splitting of the second heart sound is noted in PPHN, transposition of the great vessels, and pulmonary atresia. Heart murmurs in newborns are common in the delivery room and during the first day of life. Most of these murmurs are transient and are due to closure of the ductus arteriosus, peripheral pulmonary artery stenosis, or a small ventral septal defect. Pulses should be palpated in the upper and lower extremities (over the brachial and femoral arteries). Blood pressure in the upper and lower extremities should be measured in all patients with a murmur or heart failure. An upper-to-lower extremity gradient of more than 10 to 20 mm Hg suggests coarctation of the aorta.

Abdomen

The liver may be palpable 2 cm below the right costal margin. The spleen tip is less likely to be palpable. A left-sided liver suggests situs inversus and asplenia syndrome. Both kidneys should be palpable in the first day of life with gentle, deep palpation. The first urination occurs during the first day of life in more than 95% of normal term infants.

Abdominal masses usually represent hydronephrosis or dysplastic-multicystic kidney disease. Less often, masses indicate ovarian cysts, intestinal duplication, neuroblastoma, or mesoblastic nephroma. Masses should be evaluated immediately with ultrasound. Abdominal distention may be caused by intestinal obstructions, such as ileal atresia, meconium ileus, midgut volvulus, imperforate anus, or Hirschsprung disease. Meconium stool is passed normally within 48 hours of birth in 99% of term infants. The anus should be patent. An imperforate anus is not always visible; the first temperature taken with a rectal thermometer should be taken carefully. The abdominal wall musculature may be absent, as in prune-belly syndrome, or weak, resulting in diastasis recti. Umbilical hernias are common in African-American infants. The umbilical cord should be inspected to determine the presence of two arteries and one vein and the absence of an urachus or a herniation of abdominal contents, as occurs with an omphalocele. The latter is associated with extraintestinal problems, such as genetic trisomies and hypoglycemia (Beckwith-Wiedemann syndrome). Bleeding from the cord suggests a coagulation disorder, and a chronic discharge may be a granuloma of the umbilical stump or, less frequently, a draining omphalomesenteric cyst. Erythema around the umbilicus is omphalitis and may cause portal vein thrombophlebitis and subsequent extrahepatic portal hypertension. The herniation of bowel through the abdominal wall 2 to 3 cm lateral to the umbilicus is a gastroschisis.

Genitalia

The appearance of the genitalia varies with gestational age. At term, the testes should be descended into a well-formed pigmented and rugated scrotum. The testes occasionally are in the inguinal canal; this is more common among preterm infants, as is cryptorchidism. Scrotal swelling may represent a hernia, transient hydrocele, in utero torsion of the testes, or, rarely, dissected meconium from meconium ileus and peritonitis. Hydroceles are clear and readily seen by transillumination, whereas testicular torsion in the newborn may present as a painless, dark swelling. The urethral opening should be at the end of the penis. Epispadias or hypospadias alone should not raise concern about pseudohermaphroditism. However, if no testes are present in the scrotum and hypospadias is present, problems of sexual development should be suspected (see Chapter 177). Circumcision should be deferred with hypospadias because the foreskin is often needed for the repair. The normal prepuce is often too tight to retract in the neonatal period.

The female genitalia normally may reveal a milky white or blood-streaked vaginal discharge as a result of maternal hormone withdrawal. Mucosal tags of the labia majora are common. Distention of an imperforate hymen may produce hydrometrocolpos and a lower midline abdominal mass as a result of an enlarged uterus. Clitoral enlargement with fusion of the labial-scrotal folds (labia majora) suggests adrenogenital syndrome or exposure to masculinizing maternal hormones.

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Extremities

Examination of the extremities should involve assessment of length, symmetry, and presence of hemihypertrophy, atrophy, polydactyly, syndactyly, simian creases, absent fingers, overlapping fingers, rocker-bottom feet, clubfoot, congenital bands, fractures, and amputations.

Spine

The spine should be examined for evidence of sacral hair tufts, a dermal sinus tract above the gluteal folds, congenital scoliosis (a result of hemivertebra), and soft tissue masses such as lipomas or meningomyeloceles.

Hips

The hips should be examined for congenital dysplasia (dislocation). Gluteal fold asymmetry or leg length discrepancy is suggestive of dysplasia, but the examiner should perform the Barlow test and the Ortolani maneuver to evaluate the stability of the hip joint. These tests determine whether the femoral head can be displaced from the acetabulum (Barlow test) and then replaced (Ortolani maneuver) (see Chapter 198). The examiner’s long finger is placed over the greater trochanter, and the thumb is placed medially, just distal to the long finger. With the thighs held in midabduction, the examiner attempts to pull the femoral head gently out of the acetabulum with lateral pressure of the thumb and by rocking the knee medially. The reverse maneuver is performed by pressing the long finger on the greater trochanter and rocking the knee laterally. A clunking sensation is palpated when the femoral head leaves and returns to the acetabulum.

NEUROLOGIC ASSESSMENT

The neurologic examination should include assessment of active and passive tone, level of alertness, primary neonatal (primitive) reflexes, deep tendon reflexes, spontaneous motor activity, and cranial nerves (involving retinal examination, extraocular muscle movement, masseter power as in sucking, facial motility, hearing, and tongue function). The Moro reflex, present at birth and gone in 3 to 6 months, is one of the primary newborn reflexes. It is elicited by sudden, slight dropping of the supported head from a slightly raised supine position, which should elicit opening of the hands and extension and abduction of the arms, followed by upper extremity flexion and a cry. The palmar grasp is present by 28 weeks of age and gone by 4 months. Deep tendon reflexes may be brisk in a normal newborn; 5 to 10 beats of ankle clonus are normal. The Babinski sign is extensor or upgoing. The sensory examination can be evaluated by withdrawal of an extremity, grimace, and cry in response to painful stimuli. The rooting reflex (turning of the head toward light tactile stimulation of the perioral area) is present by 32 weeks of age.

MISCELLANEOUS DISORDERS