Objective: To assess the effects of pregnancy-induced hypertension on infant mortality in triplets stratified by gestational age at birth.
Methods: A retrospective cohort study was conducted using the linked 1995-2000 US birth/infant death database. Generalized estimating equations were used to evaluate the observed association.
Results: Pregnancy-induced hypertension was associated with lesser neonatal mortality (odds ration [OR]: 0.34, 95% CI: 0.21, 0.54), postneonatal mortality (OR: 0.54, 95% CI: 0.30, 0.99) and infant mortality (OR, 0.37, 95% CI: 0.25, 0.55) in triplets. It was also associated with a decreased risk of neonatal death (OR, 0.38; 95% CI, 0.21-0.67), postneonatal death (OR, 0.45; 95% CI, 0.21-0.97), and infant death (OR, 0.39; 95% CI, 0.24-0.64) in early preterm triplets, whereas the association was not significant in late preterm or in full-term triplets.
Conclusion: Pregnancy-induced hypertension is associated with a decreased risk of infant mortality in triplets. This effect varies with gestational age at birth.