Chapter 50 Sudden infant death syndrome
This chapter aims to provide an increased awareness and understanding of sudden infant death syndrome (SIDS) and to consider the risk factors associated with SIDS, to advise professionals and parents on minimizing risk and to enable parents to be better informed.
Sudden infant death syndrome is defined as the sudden unexpected death of a previously apparently healthy infant within the first year of life. The cause of death is frequently referred to as unexplained or unascertainable following a thorough postmortem examination. All unexpected deaths in infancy are subject to an autopsy, and where a previously undiagnosed underlying problem is found, these cases are no longer reported as SIDS (Foundation for the Study of Infant Deaths [FSID] 2009).
This chapter will address the variable terminology related to SIDS, its incidence, associated risk factors and measures to reduce the incidence, alongside national and international campaigns. In addition, the role of the midwife, health professionals and others will be considered.
Sudden infant death syndrome is sometimes referred to as sudden unexplained death in infancy or cot death. Cot death is a term frequently used by parents and the media as it reflects the fact that the death usually occurs during sleep. The term sudden infant death syndrome was brought into common usage in the late 1960s to help bereaved parents and others to ascertain that the death was as a result of an unexplained or unintentional incident; to demonstrate that the parents were not considered to be blamed for the death (Gornall 2008). A diagnosis of SIDS is reached when causes of death are excluded following postmortem examination.
The launch of the FSID ‘Back to Sleep’ campaign in 1991 saw a significant reduction in the number of SIDS cases reported (Fleming et al 2006, FSID 2007, Moon et al 2007). Sudden infant death syndrome was already in decline from 1989; nonetheless, the most significant reduction in the rate was in 1992, demonstrating the success of the ‘Reduce the risk’ campaign which encouraged parents and carers to lie babies on their back when going to sleep (FSID 2007). However, there are variations within the rates both within the UK and globally. Moon et al (2007) highlight that SIDS is the leading cause of infant mortality in the developed world. Japan and the Netherlands have the lowest rates at 0.09 and 0.1 per 1000 live births, respectively, and New Zealand has the highest rate at 0.8 per 1000 live births. Following the ‘Back to Sleep’ campaign, data collected and analysed for 2005 identified a decline in SIDS incidents in the UK, with a rate of 0.42 per 1000 live births (FSID 2009). There are variations in the figures across the UK, which may be due to a lack of uniformity in data collection. Whilst the figures continue to demonstrate a decline in SIDS across the UK, an estimated 300 babies a year will die.
Sudden infant death occurs most commonly within the first 4 to 8 weeks of life, and boys are more likely to die than girls, at a ratio of 60:40 (Moon et al 2007); previous data collection in the UK had put the peak of SIDS at 3 months (CEMACH 2008).
SIDS is multifactorial and a number of recommendations are made to advise parents and health professionals of the associated risk factors, to enable interventions to bring about continued decline in the rates.
A number of factors associated with maternal and infant health or activities have been identified as increasing the risk of SIDS.
The Department of Health, in collaboration with FSID, produced a guide on reducing the risk of ‘cot death’ (DH 2007a, 2009), which makes seven recommendations to reduce the risk of SIDS:
Social and health inequalities place disadvantaged families at increased risk. Poor access to healthcare and education may mean that parents are not able to seek out the appropriate advice or support. Families from black and ethnic minority groups continue to demonstrate poorer health outcomes (Bamfield 2007).
Whilst the aetiology of SIDS is not fully understood, modifying a number of behaviours is likely to reduce the incidence. The midwife and health professionals have a significant role in raising awareness of SIDS and the risk factors with parents, grandparents and carers, and supporting them to modify behaviours.
Lying babies on their backs to sleep appears to have brought about the most significant reduction in SIDS since the 1990s. The change in sleeping positions initially caused some concern for parents and professionals as there was considered to be an increased risk of aspiration in babies lying supine. Soft bedding surfaces and blankets may make it difficult for the baby lying prone to move his head, which could be a contributory factor in cot death. Babies sleeping on their side have an increased risk of SIDS compared to babies lying in the supine position; the increased risk can be attributed in part to babies being able to roll into a prone position. Some studies have identified that gestation, age and low birthweight can lead to an increased risk for babies lying on their side (Blair et al 2006, Oyen et al 1997); however, prematurity and low birthweight are known risk factors for poorer health outcomes, making specific links or causal factors to SIDS difficult to identify. Babies nursed in special care or neonatal intensive care units are frequently laid in the prone position as it may assist the preterm or ill baby with respiration; parents observing this practice are likely to need particular advice and guidance on nursing their baby in a supine position (Esposito et al 2007).
Newborn babies are less able to regulate their body temperature, and overheating has been associated with SIDS (Blair et al 2008); over-wrapping, warm centrally heated rooms and blankets can contribute to the baby becoming too hot. In addition, babies who are lying in the prone position will be less able to lose heat through their faces. Guidance from FSID and the Department of Health advises that the baby’s head should not be covered by too many blankets or a hat, to prevent the baby becoming too hot. The guidance also recommends that the baby is laid with the feet at the bottom of the cot or pram, ‘feet to foot’ position, to prevent the baby wriggling down under the blankets (DH 2007a, 2009).
There is some evidence that indicates that where babies sleep in the same room as their parents for the first 6 months, the incidence of SIDS is reduced. This is possibly because the parents are responsive to subtle changes in the baby’s breathing patterns and may react to the baby’s needs more quickly (Blair et al 1999). However, bed sharing remains a risk factor for SIDS: there has been a rise in the number of deaths where co-sleeping was reported, with a significant increase in co-sleeping on the sofa (Fleming et al 2006, Gornall 2008, Moon et al 2007). Advice needs to reflect that the risks are increased if the parents smoke, or have taken alcohol or drugs which can cause drowsiness (James et al 2003). Extreme tiredness is an additional risk factor, one that most parents of a young baby will experience. A national audit carried out in 2003–2004 (RCM 2005) identified that women and families need clear information regarding co-sleeping, and recommended the development of multidisciplinary and evidence-based approaches to training and information for parents.
Reflective activity 50.1
Visit the FSID website and look at the advice and guidance for professionals and parents.
Watch the video clip ‘Safe sleep for babies’: www.fsid.org.uk/safe-sleep-video.html.
Smoking in pregnancy is known to increase the risk of preterm birth and low-birthweight babies, two factors that are associated with an increased incidence of SIDS. A number of studies reviewed by FSID suggest that the risks of SIDS and smoking in pregnancy cannot simply be attributed to prematurity and low birthweight; smoking remains a contributory factor when other confounding variables – for example, maternal age, parity, marital status and breastfeeding – are considered (FSID 2007, Moon et al 2007; Shah et al 2006). Whilst some of the evidence reviewed was undertaken in the 1990s, the conclusions were similar and suggested that the more cigarettes smoked in pregnancy the higher the risk of SIDS. The evidence highlights the benefits of encouraging women to reduce the number of cigarettes smoked in pregnancy if they are unable to stop completely.
Smoking near or in the same room as a baby continues to pose a risk of cot death – a baby who regularly spends an hour a day in a smoky environment is twice as likely to die from SIDS as a baby in a smoke-free environment. The advice not to smoke in pregnancy and around the baby applies to both the mother and father. A poll undertaken by FSID highlighted that seven in ten parents were unaware of the risk of smoking in the home and the link with cot death, despite numerous campaigns and health warnings about the risks of smoking (FSID 2008).
Evidence indicates that breastfeeding is an important contributory factor in reducing the risk of SIDS (Fleming et al 2006, FSID 2007). The health benefits of breastfeeding are well reported and the link with a reduced risk of SIDS could be attributed to the IgA antibodies found in breast milk, which fight off bacterial toxins (Gordon et al 1999). Discouraging bed sharing may have a detrimental effect on the duration of breastfeeding. A UNICEF statement on mother–infant bed sharing advises that parents need to understand the benefits of promoting breastfeeding and that the risks of bed sharing are increased when the mother smokes (UNICEF 2005). There is some evidence that the use of dummies or pacifiers can reduce the incidence of SIDS (Mitchell et al 2006); however, the adverse effect of dummies on the duration of breastfeeding and increased risk of respiratory and gastrointestinal infections indicate that further studies need to be undertaken (Fleming et al 2000, Wickham 2006).
Antenatal care will help to improve the wellbeing of the mother, fetus and baby through identification of risk factors, advising on modifying behaviours and seeking medical intervention where appropriate. This role will help to reduce some of the possible associated risk factors for SIDS. The midwife is in an ideal position to advise parents and the wider family on general health and raise awareness of SIDS. The midwife will also work in collaboration with general practitioners, health visitors and other practitioners to advise parents on modifying behaviours, for example, smoking cessation (DH 2007b).
Every unexpected death is subjected to scrutiny by the coroner, and the police are required to interview the family and may take samples of clothing and bedding away as part of the in-depth review. On top of the devastating death of a child, the parents’ distress is likely to be exacerbated by the intense investigations. The investigation needs to be undertaken sensitively; the parents are likely to have many questions about the death of their baby and it is important that they are advised of any findings from the investigation.
Families who have experienced the death of a baby will understandably be concerned about the health of future babies, particularly if the cause of death is not ascertained. FSID has set up a programme of support for these families, called ‘Care of Next Infant’ (CONI). This uses the skills and support of the paediatrician, obstetrician, family doctor, midwife, health visitor and a local CONI coordinator. The family determines the level of support and it can include home visits to assess wellbeing and provide practical advice on room temperature and signs of ill health.
Conclusion
The death of a baby is devastating for parents, the family and health carers. Approximately 300 babies a year in the UK will succumb to SIDS. The causes are unknown but appear to be multifactorial. Advising parents on modifying behaviours, for example, the reduction or cessation of smoking, ensuring a suitable sleeping environment and encouraging breastfeeding, helps to minimize the risk factors.
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