A recent study is reviving the debate over whether it's beneficial-or dangerous-for parents to sleep with their babies. Findings showed that accidental strangulation and suffocation death rates for U.S. infants quadrupled between 1984 and 2004.

Shapiro-Mendoza and colleagues analyzed 20 years of data from the National Center for Health Statistics (NCHS) and discovered that as deaths attributable to sudden infant death syndrome declined, deaths from asphyxiation in bed dramatically increased, rising from 2.8 to 12.5 deaths per 100,000 live births. The nature of these accidents-an infant caught between headboard and bed, for instance-was noted only in reports from 2003-04, the first years in which the NCHS documented cause of death. Being trapped beneath another person, known as "overlay," was common, accounting for a third of the suffocation or strangulation deaths; suffocation by bedding or by being wedged or trapped were each responsible for 14% of deaths. These deaths tended to occur on adult beds (27.5%), on sofas (10%), and in cribs (6.8%).

Although the authors conclude that the reason for the increase in deaths is "unknown," a few suspects have emerged. One is improved identification methods: what once would have been classified as "cause unknown" is now filed under suffocation and strangulation. The other is cosleeping (bed sharing), which became popular during roughly the same 20-year period as the one in which the infant deaths increased; in the study, 53.3% of the 2003-04 cases reported bed sharing.

The American Academy of Pediatrics thinks the practice is unsafe; this January, the organization reissued a 2005 advisory against it (see http://bit.ly/1hwbpr). Like many groups, however, it advocates breastfeeding-one of the major reasons parents share beds with infants. "It helps moms get in sync with and bond with their babies," says Diane L. Spatz, associate professor at the University of Pennsylvania School of Nursing. "If the baby is in close proximity and starts that grunting noise, the mom will instantly know her baby is hungry. Clinical cues are hard to sense from far away."

There's even speculation that introducing breastfeeding to the bed-sharing equation makes it safer. "Some of the literature shows the rate of entrapment to be highest in populations where breastfeeding rates are lowest," says Spatz, adding that parents often create unsafe environments in cribs (think stuffed animals and heavy comforters), where cosleeping doesn't occur.

But it's not simply that cosleeping makes breastfeeding and bonding easier. "Sometimes it's the only way to get any sleep," says Spatz. "Besides, worldwide, the cultural norm is the family bed." Consequently, many parents are unlikely to abandon bed sharing even when told to. Instead, nurses should counsel families on safe cosleeping, telling them to avoid puffy bedding, for instance, and (if they can afford it) purchase a "cosleeper"-a three-sided bassinet placed alongside the bed, near the mother. Drugs, alcohol, cigarettes, and obesity also contribute to unsafe cosleeping conditions.

Spatz acknowledges that it's hard to explain why infant deaths increased in the NCHS study, "but unless we know concretely that it was due to cosleeping, I don't think it's wise to place the blame there," she says. "Instead, health care providers must have honest conversations with families about any practices that may put the child at risk."

Shapiro-Mendoza CK, et al. Pediatrics 2009;123(2):533-9.

Bunny Wong