Why One Sids Death May Lead to Another

NEW YORK (Reuters Health) - Women who have an infant that dies from sudden infant death syndrome (SIDS) are more likely in their subsequent pregnancies to deliver infants who are born preterm or "small for gestational age," investigators from the UK have found.

Because these complications increase the risk of SIDS, these data help explain why some women have more than one infant who succumbs to SIDS.

Statistics show that women who have one baby who dies from SIDS are roughly five times more likely than other women to have another SIDS occurrence; the mechanism underlying the increased risk of recurrence is not known.

To investigate, Dr. Gordon C. S. Smith from Cambridge University and his team used Scottish databases to identify a group of women who had consecutive births between 1985 and 2001.

Among 258,000 women, the first infant of 332 women and the second infant of 203 women died from SIDS. One woman had two consecutive infants die with a diagnosis of SIDS.

Women whose previous infant died were two to three times more likely to deliver an infant that was deemed small for gestational age or to have a preterm birth, both of which are associated with increased risk of SIDS.

Multivariate analysis showed that these associations were explained by maternal characteristics such as age, marital status and smoking, and obstetric complications.

These findings, investigators write in The Lancet, "provide direct evidence that the risk of SIDS after a given birth is not statistically independent on whether previous infants died."

SOURCE: The Lancet December 17, 2005.