Risk of neonatal adverse pregnancy outcome in twin pregnancies conceived via in-vitro fertilization

This cohort study assessed the stillbirth rate and neonatal comorbidities associated with the timing of delivery in twin pregnancies following in-vitro fertilization (IVF) treatments.

This retrospective study encompassed 1596 twin pregnancies and categorized participants into spontaneous conception (SC) and IVF groups. The investigation initially assessed the impact of IVF on maternal and neonatal outcomes post-delivery, followed by an exploration of the prospective risk of stillbirth and incidence of stillbirth under IVF and gestational age stratification. Subsequently, multivariable Cox regression analysis was conducted to determine any significant difference in twin mortality with or without IVF. Additionally, post-delivery maternal and neonatal comorbidities rates are examined within the context of IVF and gestational age categories using multivariable logistic regression and restricted cubic splines to investigate trends in neonatal comorbidities with and without IVF. The objective was to optimize delivery timing to balance the risk of stillbirth associated with continued pregnancy against the risks of late preterm birth and neonatal complications, thereby achieving the best possible maternal and infant health outcomes.

The study revealed that twin pregnancies conceived through IVF were associated with higher maternal age and pre-pregnancy body mass index (PBMI) compared to the SC group, yet there were no significant differences in the incidence of maternal and neonatal outcomes post-delivery. While the prospective risk of stillbirth and the rate of stillbirth was higher in the IVF group at each delivery time point, these differences are not statistically significant after adjusting for confounding factors in the Cox regression analysis. The incidence of post-delivery maternal and neonatal outcomes in the IVF group was not significantly different from the SC group across various delivery times and after adjustment using logistic regression and restricted cubic splines, gestational age significantly affected the risk of composite neonatal outcomes (p < 0.05). In the IVF group, compared to a median gestational age of 37 weeks, both late preterm and pregnancies delivered beyond 37 weeks showed an increasing trend in the risk of composite neonatal outcomes. Conversely, in the SC group, the risk of composite neonatal outcomes showed a decreasing trend with the extension of gestational weeks at delivery.

In twin pregnancies resulting from IVF treatment, both the prospective risk of stillbirth and the rate of stillbirth were higher compared to those in the SC group. Considering the associated risks of stillbirth and neonatal complications, delivery around 37 weeks may be associated with more favorable outcomes. However, this observation does not establish 37 weeks as the definitive optimal time for delivery. The findings suggest that further research is needed to explore the best delivery timing for IVF twin pregnancies and to guide clinical decision-making for optimizing pregnancy outcomes.