Sleep issues quickly become front and center for the majority of new parents. One of the decisions they face is where their newborn will sleep and how to reduce the risk of SIDS.
SIDS stands for sudden infant death syndrome, when a baby dies for unexplained reasons.
A recent study found an increased risk for SIDS among babies who shared a bed with their parents, even if the parents didn't smoke and the baby was breastfed.
This study had limitations but contains valuable information about risks to help parents decide which sleeping methods are best for their family.
The study, led by Robert Carpenter, of the Department of Medical Statistics at the London School of Hygiene and Tropical Medicine in the United Kingdom, examined SIDS rates among parents who did and did not share a bed with their child.
The researchers gathered the data from five previous studies that compared cases of SIDS deaths to children used as controls (who did not die).
The total number of babies involved after data was gathered from all five studies was 1,472 babies who died of SIDS and 4,679 babies used as control comparisons.
Among the SIDS cases, 22.2 percent of the infants had been sharing a bed with their parents when they died.
Among the control group cases, 9.6 percent of the parents reported that their infant had slept in their bed with them the morning of the interview for the study.
The researchers then calculated the risk for SIDS when infants shared a bed with their parents after taking into account other risk factors.
Other factors that might affect SIDS rates include parents who smoke or drink alcohol, younger babies and whether a baby is breastfed.
The researchers calculated that babies under 3 months old who shared a bed with their parents were at a risk five times higher for SIDS than babies who were sleeping in the parents' room but not sharing a bed. This risk remained even when the baby was breastfed and neither parent smoked.
When the researchers considered a breastfed baby whose parents did not smoke and who had no other risk factors, the risk of SIDS was 2.7 times higher for bed-sharing than for room-sharing without bed-sharing.
The researchers estimated that the risk of SIDS for a baby sleeping in his or her parent's room, but not in their bed, was 8 SIDS deaths out of every 100,000 babies.
For babies who shared a bed with their parents, the risk was calculated at 23 SIDS deaths out of every 100,000 babies.
However, the study has several limitations that could substantially change the risk for bed-sharing babies.
The authors attempted to control for alcohol use by the mothers, but in three of the five studies, mothers were not asked whether they had used alcohol or illegal drugs within the previous 24 hours.
Further, none of the parents were asked whether they intended to share a bed or if they had fallen asleep with the baby accidentally or temporarily.
Most importantly, the parents were not asked how they were sharing a bed, whether they knew of the best ways to reduce an infant death while sharing a bed or whether they were implementing any precautions to reduce the risk.
In addition, SIDS deaths and suffocation deaths are reported together as "unexplained deaths in infancy." Therefore, the data separating SIDS deaths from suffocation deaths was not available.
The older the baby was, the lower the risk of SIDS was. However, the risk for SIDS increased for babies if either parent smoked and if the mother used alcohol or illegal drugs, both for bed-sharing and for room-sharing babies.
Among babies placed in their cribs or bassinets, the risk for SIDS was highest when a baby was placed on his or her stomach.
The study was published May 20 in the journal BMJ Open.
The research did not receive external funding on its own. Each of the previous studies analyzed in this larger one received their own funding from the following organizations: The European Union and the Foundation for the Study of Infant Deaths, Irish Department of Health and Children, The Health Research Council of New Zealand, the Scottish Cot Death Trust and the Federal Ministry of Education and Research in Germany.
One author is a steering committee member for Lullaby Trust's Care of Next Infant, CONI. Another author is supported by Cure Kids, and another is funded by the Economic and Social Research Council. No other disclosures were reported.