Subsequent Infants Are at Risk After SIDS Death


Women who have had a baby who died from SIDS are more likely to have preterm birth or intrauterine growth restriction in their next pregnancy than are other women, reported Dr. Gordon C.S. Smith of the University of Cambridge (England) and his associates.

Similarly, women who have had a preterm or small-for-gestational-age (SGA) infant in one pregnancy are more likely to have a baby who dies from SIDS in the next pregnancy.

These associations were discovered in an analysis of large, comprehensive medical databases, and they strongly persisted when the data were adjusted for numerous maternal and demographic factors. However, the associations disappeared when gestational age and intrauterine growth restriction (IUGR) were factored into the analysis. From this finding, the investigators concluded that the link between SIDS and preterm birth/intrauterine growth restriction in other pregnancies is due to an as yet unknown maternal factor that underlies both disorders.

In the analysis, Dr. Smith and his associates reviewed information in a database on all Scottish in-hospital births, another database on all perinatal deaths in Scotland, and a third database on all Scottish birth and death records. They narrowed their study to focus on the records of 258,096 women who had one singleton birth between 1985 and 2001 and a second singleton birth between 1992 and 2001.

There were 332 women whose first infant died from SIDS, and 203 whose second infant died from SIDS, the investigators said (Lancet 2005;366:2107–11).

Women whose first infant died from SIDS were two to three times more likely to have a preterm delivery and two to three times more likely to deliver an SGA infant in the next pregnancy than were other women.

In women whose first delivery was preterm or whose first pregnancy was affected by IUGR, the risk of SIDS was elevated in the baby delivered in the subsequent pregnancy.

“We speculate that the association between SIDS in one pregnancy and obstetric complications in other pregnancies partly explains the tendency for SIDS events to recur,” they said.

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