Introduction: Our study compared the prospective risks of intrauterine fetal death (IUFD), neonatal death (NND), perinatal death (PND), and neonatal morbidities in monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin pregnancies.
Methods: This retrospective cohort study included twin pregnancies who had antenatal care and delivery in a public hospital from 2011 to 2018. Exclusion criteria included monoamnionicity, one/both twin miscarriage, twin-twin transfusion syndrome, or lethal congenital abnormalities. All twins were managed in multiple pregnancy clinic with standardized protocols. Gestational age-specific IUFD, NND, PND, and neonatal morbidity rates were compared according to chorionicity.
Results: Three hundred seventy-eight MCDA and 1282 DCDA twins were included. MCDA twins had higher risks of PND (1.9% vs. 0.7% in DCDA twins, p = 0.05), composite neonatal morbidity (p = 0.01), preterm delivery (p < 0.01), and low birth weight (p < 0.01). The prospective risk of IUFD was 0.6% and 0.4% for MCDA and DCDA twins, respectively after 34 weeks' gestation. No NND occurred among deliveries after 30 weeks. The risk of neonatal morbidity of MCDA twins fell from 22.7% at 34 weeks to 2.7% at 37 weeks (p < 0.01). For DCDA twins, the risk of morbidity fell insignificantly from 36 to 38 weeks (4.0% vs. 3.4%, p = 0.60). Logistic regression analysis suggested that the increased risk of perinatal morbidities was related to the higher rate of preterm delivery in MCDA twins rather than chorionicity.
Conclusion: With close fetal monitoring, the risk of late IUFD in twin pregnancies without major complications is low. Perinatal morbidity can be minimized by avoiding late preterm deliveries in twin pregnancies.
Keywords: neonatal mortality; perinatal mortality; stillbirth; twins.
© 2021 Japan Society of Obstetrics and Gynecology.