Is in-vitro fertilization a risk factor for perinatal morbidity in late term pregnancies beyond 41 weeks of gestation? A comparative retrospective study.

OBJECTIVE: To assess whether in vitro fertilization (IVF) is associated with increased perinatal morbidity and mortality in late-term pregnancies. STUDY DESIGN: We conducted a retrospective single-center cohort study including all women with singleton cephalic pregnancies delivered at ≥ 41 weeks of gestation between 2018 and 2022. Women who conceived through IVF (including IVF with oocyte donation) were compared with those with spontaneous conception. The primary outcome was a composite of perinatal morbidity and mortality. Multivariable logistic regression was used to adjust for maternal age, body mass index, parity, and geographic origin. Sensitivity and subgroup analyses were performed. RESULTS: Among 4,126 women, 353 (8.6%) conceived through IVF. Women in the IVF group were older and more frequently nulliparous. The composite perinatal outcome was higher in the IVF group in unadjusted analysis (12.5% vs 9.0%, p=0.04), but not after adjustment (adjusted odds ratio [aOR] 1.36, 95% CI 0.94-1.93). Results were unchanged in sensitivity analysis restricted to expectant management and in the oocyte donation subgroup. IVF pregnancies were associated with higher rates of labor induction, cesarean delivery, hypertensive disorders, and postpartum hemorrhage. CONCLUSION: In late-term pregnancies, IVF was not independently associated with increased perinatal morbidity or mortality.