Maternal, Perinatal and Neonatal Outcomes of Triplet Pregnancies According to Chorionicity: Our 15-Year Experience in a Tertiary-Level Center.

: The goal of this study was to evaluate the effect of chorionicity on maternal, fetal and neonatal morbidity and mortality in triplet pregnancies in our environment. : A retrospective observational study was carried out on triplet pregnancies that were delivered in a tertiary center between 2006 and 2020. A total of 76 pregnant women, 228 fetuses and 226 live newborns were analyzed. Of these triplet pregnancies, half were non-trichorionic. We analyzed maternal characteristics and obstetric, fetal, perinatal and neonatal complications based on their chorionicity, comparing trichorionic vs. non-trichorionic triplet pregnancies. Prematurity was defined as <34 weeks. We measured perinatal and neonatal mortality, composite neonatal morbidity and composite maternal morbidity. : Newborns with a monochorionic component had a lower gestational age at birth, presented greater prematurity under 34 weeks, lower birth weight, greater probability of birth weight under 2000 g and an APGAR score below 7 at 5 min after birth, more respiratory distress syndrome and, overall, higher composite neonatal morbidity. The monochorionic component of triple pregnancies may entail the development of complications intrinsic to shared circulation and require premature elective termination. This greater prematurity is also associated with a lower birth weight and to the main neonatal complications observed. These findings are in line with those that were previously published in the meta-analysis by our research group and previous literature. : Triplet gestations with a monochorionic component present a higher risk of obstetric, fetal and neonatal morbidity and mortality.