Maternal pre-eclampsia/eclampsia and the risk of sudden infant death syndrome in offspring

To determine whether maternal exposure to pre-eclampsia/eclampsia during pr egnancy increases the risk of sudden infant death syndrome (SIDS) in offspr ing, we conducted a population-based case-control study using the Californi a linked birth and death certificate data. All infants who died of SIDS (IC D-9 code 798.0) during 1989-91 were identified as cases. More than 96% of t he identified SIDS cases were diagnosed through autopsy. Ten controls who d id not die from SIDS were randomly selected for each case from the birth ce rtificate matched to the case on the year of birth. Among 2029 cases and 21 037 controls included in the final analysis, mothers of 49 cases (2.4%) an d 406 controls (1.9%) had a diagnosis of either pre-eclampsia or eclampsia noted on the birth certificate. After adjustment for maternal age, prenatal smoking, race/ethnicity, parity, maternal education, gestational age at th e initial visit for prenatal care, infant year of birth and infant sex, mat ernal pre-eclampsia/eclampsia during pregnancy was associated with a 50% in creased risk of SIDS in the offspring (odds ratio = 1.5, 95% confidence int erval 1.1, 2.0). Potential under-reporting of pre-eclampsia/eclampsia on th e birth certificates was likely to be non-differential and is unlikely to e xplain the finding. Fetal hypoxia resulting from pre-eclampsia/eclampsia or immunological aetiology affecting the risk of both pre-eclampsia/eclampsia and SIDS may explain the finding.