EVIDENCE-BASED ANSWER
Non-supine sleep position and parental tobacco use are known risk factors for sudden infant death syndrome (SIDS). Recent studies show that co-sleeping (bed sharing) slightly increases the overall risk of SIDS (strength of recommendation [SOR]: B) and is greatest for infants less than 11 weeks old (SOR: B). The relationship between bed sharing and SIDS is strongest for infants whose parents use tobacco (SOR: B). Infants who sleep in a room separate from their caregivers or on a couch or an armchair are at increased risk for SIDS (SOR: B). Using bedding accessories such as duvets or pillows may increase an infant’s risk of SIDS (SOR: B).
CLINICAL COMMENTARY
Despite its weakness, counsel families based on what evidence is available
Perry Brown, MD, FAAP
Family Medicine Residency of Idaho, Boise; University of Washington School of Medicine, Seattle
This Clinical Inquiry reviews evidence about one of the most controversial and emotion-laden issues of infancy—where should baby sleep? Of course a parent wants to minimize the risk of SIDS, and this review has some evidence of how to accomplish this.
However, often there are pragmatic obstacles to an ideal sleeping arrangement for an infant. One obstacle is exhaustion. Parents are awake multiple times per night with a young infant, and having the infant bed-share is often easier and more efficient for breastfeeding mothers. Poverty is another obstacle—the family may be unable to afford a crib or bassinet. There can also be cultural obstacles, in that certain cultures traditionally bed-share with infants and children. Physicians are deterred from addressing bed-sharing with families, because the discussion is often lengthy and the family is sometimes defensive.
Despite generally weak evidence on this topic, we must counsel families based on what evidence is available, and not shy away from this discussion. Few things are worse than retrospectively wondering if a case of SIDS could have been prevented.
Evidence summary
SIDS is defined as the sudden death of an infant aged <1 year of age that remains unexplained after a thorough investigation. The SIDS mortality rate is 0.57 per 1000 infants, with peak incidence among 1- to 5-month-olds.1 Non-supine sleep position and parental tobacco use are established risk factors for SIDS and therefore are not explicitly addressed in this review. Using the 9 best-designed case-control studies published to date, each of which used multivariate analysis to control for infant sleep position and parental tobacco use (among other confounders), we evaluated co-sleeping, room sharing, sleep surfaces, and bedding accessories as risk factors for SIDS (TABLE).
TABLE
Sleeping arrangements and their relationship to SIDS
| SLEEP ARRANGEMENT | RISK ESTIMATE* |
|---|---|
| Co-sleeping2-10 | Overall OR: 2.0 (1.2–3.3)4 to 16.47 (3.72–72.75)9 |
| OR if parent is smoker: 4.55 (2.63–7.88)10 to 17.7 (10.3–20.0)8 | |
| OR if parent is nonsmoker: 0.98 (0.44–2.18)10 to 2.20 (0.99–4.91)7 | |
| Sleeping in separate rooms5,6,8,11 | OR: 3.13 (1.82–5.26)8 to 10.49 (4.26–25.89)5 |
| Sleeping on couch or chair4-6,9 | 55 non-bed sleepers among 772 total SIDS cases (7.1%) vs 8 non-bed sleepers among 1854 total controls (0.4%)† |
| Soft bedding accessories4,7-9 | OR for use of pillow: 1.03 (0.66–1.59)7 to 2.8 (1.3–6.2)4 |
| OR for use of duvet: 1.32 (0.41–4.15)9 vs 1.82 (1.30–2.58)8 | |
| *All studies used multivariate analyses and controlled for tobacco use and infant sleep position. Risk estimates are lowest to highest OR with 95% CI (unless otherwise specified). | |
| †Aggregated data from 4 studies given small numbers. | |
| SIDS, sudden infant death syndrome; OR, odds ratio; CI, confidence interval. | |
A number of factors complicated this review. First, although all studies evaluated infants through 1 year of age, some excluded infants <7 days or <28 days old. Second, studies examined different sleep periods; 2 focused on usual sleeping arrangements,2,3 5 on sleeping arrangement immediately prior to death,4-8 and 2 evaluated both usual and last sleep arrangements.9,10 Third, variations in definitions of each risk factor and differences in the confounders controlled for made comparing studies challenging. Fourth, given the difficulty in studying infant deaths, the best evidence available comes from case-control studies.
Co-sleeping. Overall, 5 of 6 studies demonstrated co-sleeping to be an independent risk factor for SIDS (odds ratio [OR]=2.0–16.5),2,4-7,9 especially for infants younger than 11 weeks old.6,8 Four stratified analyses indicate that the risk of co-sleeping is greatest among infants of smokers (OR=4.6–17.7) as compared with infants of nonsmokers (OR=1.0–2.2).3,7,8,10 Some descriptive studies suggest potential benefits of co-sleeping, such as improved breastfeeding and maternal-infant bonding, but these benefits have not been quantified.1