Induction of labor and risk of sudden infant death syndrome

To investigate whether induction of labor is related to the occurrence of sudden infant death syndrome (SIDS) using a population-based, case-control study.

Cases comprised infants born between 1984-1988 in Washington state who died of SIDS according to their death certificate (ICD-9-CM 798.0) (N = 728). For comparison, we randomly selected a group of infants born in these same years who did not die of SIDS (N = 3021). Information regarding the pregnancy, labor, delivery, and condition of the newborn was obtained from the infants' birth certificates.

Among the indications for induction that were examined, we found a slightly elevated risk of SIDS associated with advanced gestational age (greater than 41 completed menstrual weeks) (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.0-1.8). A similar proportion of cases and controls had induced labors (OR 1.2, 95% CI 0.7-2.1). Although there was little or no apparent risk associated with induction among infants who had term gestations (37-41 completed menstrual weeks; OR 1.2, 95% CI 0.6-2.2), an increased risk was found among infants who had gestations of 42 weeks or greater (OR 3.0, 95% CI 0.7-12.5). We did not observe this trend with augmentation of labor.

Our findings do not support an overall association between the methods used for induction of labor in the United States and the occurrence of SIDS. The elevated risk of SIDS observed in relation to induction of labor among infants who had post-term gestations raises the possibility that infants who do not spontaneously initiate labor may suffer some neuroregulatory or other abnormality involved in the pathogenesis of SIDS.