Monochorionic twin pregnancies conceived through assisted reproduction: Maternal and perinatal clinical outcomes

Monochorionic (MC) twin pregnancies are at high risk of maternal, fetal, and neonatal complications. Assisted reproductive technology (ART) increases the incidence of MC twinning, but its impact on pregnancy outcomes in this subgroup remains unclear. This study aimed to investigate whether conception via ART is associated with adverse maternal and perinatal outcomes in MC twin pregnancies and to highlight key areas for future research.

A retrospective observational study was conducted on MC twin and multifetal pregnancies referred to a tertiary fetal medicine center from 2020 to 2023. A total of 100 ART-conceived MC pregnancies (77 homologous ART and 23 egg donation) were compared to 343 spontaneously conceived MC pregnancies. Maternal, fetal, and neonatal outcomes were analyzed. Adjusted odds ratios (aOR) were estimated using logistic regression, and generalized estimating equations were applied to account for within-twin pair correlation.

Results are presented for the entire population and for MC diamniotic (MCDA) pregnancies only. Women with ART-conceived MC pregnancies were older and more often nulliparous compared to those with spontaneous conception (p < 0.01), yet exhibited similar rates of preterm delivery and cesarean section. ART was associated with higher risk of maternal complications (p < 0.01), particularly hypertensive disorders (p = 0.02). Fetal demise and postnatal morbidity occurred more frequently in ART pregnancies, although neither association remained statistically significant after adjustment for within-twin pair correlation or in MCDA-only analyses. ART-conceived twins had lower rates of twin-to-twin transfusion syndrome but poorer survival after laser treatment (p < 0.01). Overall survival did not differ across groups.

ART-conceived MC pregnancies show an increased burden of maternal complications. Fetal and neonatal outcomes did not differ significantly from those of spontaneously conceived pregnancies after adjustments, despite higher point estimates for adverse outcomes. In the context of the global rise in ART use, these findings underscore the need for further clinical and basic-science research to better characterize the magnitude and mechanisms of ART-associated risks in MC pregnancies.