Effects of fetal presentation on mode of delivery in 26 143 twin pregnancies: A nationwide, population-based observational study of 31-year real-world data.

Objective: To describe the rate of combinations of fetal lies and presentations in twin pregnancies at delivery and to assess the effects of fetal lies and presentations on mode of delivery as well as fetal and maternal birth outcomes.

Methods: This population-based cohort study used real-world data from the Medical Birth Registry of Norway and included all twin births (n = 26 143) in Norway during 1988-2018. Logistic Regression Analysis was Applied. Main outcome measures were planned and actual modes of delivery categorized into vaginal deliveries and cesarean sections. Secondary outcomes were postpartum hemorrhage and intrapartum stillbirth.

Results: Most twin births were planned as vaginal deliveries (83.4%, 21 811/26 143), of which (65.9%, 14 371/21 811) were successful. Vaginal delivery was more often successful in parous than in nulliparous women, or if the first or both twins were in cephalic presentation compared with non-cephalic presentation of the first or both twins. Planned cesarean section was more likely to be chosen if the first or both twins were in non-cephalic presentation than if they were in cephalic presentation. Maternal parity, demographic and obstetric risk factors had little or no effect on the association between twin presentations and planned or actual delivery mode.

Conclusions: More than half of women with a twin pregnancy had a successful vaginal delivery. Keeping the option of the vaginal route as the primary mode of delivery in a twin pregnancy maintains the right of the woman to have a vaginal delivery and avoid a uterine scar.