Objective: To investigate outcomes in spontaneous and induced twin deliveries. Secondary aims were to study impact of delivery interval and breech presentation of the first twin.
Methods: This retrospective cohort study comprised 354 twin deliveries at a tertiary Norwegian hospital. Spontaneous labor onset and induction of labor were compared in women with planned vaginal delivery and gestational age ≥ 34 weeks. The main outcome was intrapartum cesarean section. Secondary outcomes were umbilical arterial pH and five-minute Apgar scores.
Results: Among the induced labors, 63/229 (27.5%) women underwent intrapartum cesarean section, compared to 45/125 (36%) in spontaneous labors (P = 0.10). Odds ratio for intrapartum cesarean section in induced labors was 0.65 (95% CI 0.40-1.04) after adjusting for maternal age and parity. Median umbilical arterial pH was significantly lower in the second twins in both spontaneous and induced labors, 7.28 (6.94-7.43) vs. 7.32 (7.16-7.42), and 7.27 (6.90-7.48) vs. 7.29 (7.08-7.45), respectively. pH < 7.00 rarely occurred. Second twins born after a delivery interval > 30 min had a significantly higher frequency of pH < 7.10 than those with a shorter interval, P < 0.01. No significant difference was found in frequency of pH < 7.10 between breech-presenting and cephalic-presenting first twins (P = 0.65). One unexpected intrapartum fetal death occurred after labor induction.
Conclusion: Our results support spontaneous onset and induction of labor as safe. Intrapartum cesarean section rates did not differ significantly between spontaneous and induced labors. Delivery interval > 30 min was associated with a lower pH in the second twin.
Keywords: Cesarean; Delivery; High-risk pregnancy; Induction of labor; Pregnancy.
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