Supplementary Material for: Outcome of Multifetal Pregnancy Reduction in Women with a Dichorionic Triamniotic Triplet Pregnancy to a Singleton Pregnancy: A Retrospective Nationwide Cohort Study

<b><i>Objective:</i></b> To study the pregnancy outcomes of women with a dichorionic triamniotic triplet pregnancy that was reduced to a singleton pregnancy and to review the literature. <b><i>Methods:</i></b> We performed a nationwide retrospective cohort study. We compared time to delivery and perinatal mortality in dichorionic triplet pregnancies reduced to singletons with ongoing dichorionic triplet pregnancies and primary singleton pregnancies. Additionally, we reviewed the literature on the subject. <b><i>Results:</i></b> We studied 46 women with a reduced dichorionic triplet pregnancy and 42 women with an ongoing dichorionic triplet pregnancy. Median gestational age at delivery was 38.7 vs. 32.8 weeks, respectively (p < 0.001). Delivery <24 weeks occurred in 9 (19.6%) women with a reduced triplet pregnancy and 4 (9.5%) with an ongoing triplet pregnancy (p = 0.19). Perinatal survival rates between the reduced group and the ongoing triplet group were not significantly different. <b><i>Conclusion:</i></b> Multifetal pregnancy reduction in women with a dichorionic triplet pregnancy to a singleton pregnancy prolongs median gestational age at birth. No statistically significant association was found with miscarriage and perinatal survival rates.