Mode of delivery of twin gestation with very low birthweight: is vaginal delivery safe?

OBJECTIVE: The purpose of this study was to determine whether planned vaginal delivery is associated with increased risk of perinatal death and morbidity in twin pregnancies that are complicated by a very low birthweight of the second twin.

STUDY DESIGN: We conducted a retrospective cohort study of twin pregnancies in which the second twin's birthweight was ≤1500 g. One hundred ninety-three twin gestations met the study criteria; patients were classified into 2 groups according to the planned mode of delivery: (1) cesarean delivery (n = 142) and (2) vaginal delivery (n = 51). In the vaginal delivery group, 21 pairs were in cephalic-cephalic presentation at the time of delivery; 28 pairs were cephalic-noncephalic, and 2 pairs were noncephalic-noncephalic. Composite adverse neonatal outcome was defined as the presence of neonatal death, respiratory distress syndrome, sepsis, necrotizing enterocolitis, or intraventricular hemorrhage grade 3-4.

RESULTS: Trial of vaginal delivery was successful for both twins in 90.5% of cephalic-cephalic twins and 96.4% in cephalic-noncephalic twins. The rate of intraventricular hemorrhage was significantly higher in the vaginal delivery group (29.4% vs 8.5%, respectively; P = .013; adjusted odds ratio [OR], 3.65; 95% confidence interval [CI], 1.32-10.1). The increased risk of intraventricular hemorrhage in the vaginal delivery groups was evident in both twin A (17.6% vs 7.0%; P = .029) and twin B (15.7% vs 4.9%; P = .014); however, these differences were not significant after adjustment for possible confounders (twin A: adjusted OR, 1.79; 95% CI, 0.58-5.55; twin B: adjusted OR, 2.13; 95% CI, 0.63-7.25). In addition, subgroup analysis revealed that both cephalic-cephalic and cephalic-noncephalic twins who were delivered vaginally had increased risk for intraventricular hemorrhage. There were no significant differences between the cesarean and vaginal delivery groups in the rates of Apgar score <7 at 5 minutes, arterial cord pH <7.1, composite adverse neonatal outcome, and neonatal mortality rate. However, the rate of respiratory distress syndrome was significantly lower in the vaginal delivery group (66.7% vs 69%; P = .042; OR, 0.34; 95% CI, 0.12-0.96).

CONCLUSION: Vaginal delivery of very low birthweight twins is associated with an increased risk of intraventricular hemorrhage, regardless of presentation. Because of the small sample size and the retrospective cohort design, large prospective randomized studies are needed.