Abstract
Objective We evaluated risk of subsequent stillbirth (SB) according to gestational age at initial
SB.
Study Design We retrospectively reviewed a cohort of women delivering a singleton SB with at least
one subsequent pregnancy. Relative risks (RRs) were calculated using an initial SB
gestational age of 36 to < 40 weeks as the referent. Multivariable logistic regression
accounted for potential confounders.
Results In all, 2,887 mothers and 5,090 subsequent births met inclusion criteria. For the
immediately next pregnancy, the linear trend for gestational age was not significant
(RR 0.41; 95% confidence interval [CI] 0.03 to 5.53). However, women with index SBs
occurring between 20 and 236/7 weeks' gestation had a RR for subsequent stillbirth of 2.9 (95% CI 1.2 to 7.1). When
including subsequent pregnancies, the test for trend for gestational age was nonsignificant
(RR 1.5; 95% CI 0.3 to 8.7). However, women suffering a stillbirth between 200/7 and 236/7 weeks' gestation in the index pregnancy had an almost threefold increase in the risk
of subsequent stillbirth. Women suffering an index stillbirth between 280/7 and 316/7 weeks' and after 40 weeks' gestation had a 2.5- to 3.5-fold increased risk of subsequent
SB.
Conclusions Gestational age at initial SB predicts risk of recurrent SB. This effect is most
pronounced in women with very preterm or with postterm pregnancies.
Keywords
pregnancy complications - recurrence risk - stillbirth
