Mode of delivery among preterm twins and offspring health, a retrospective cohort study

Although cesarean delivery (CD) has been linked to long-term health risks in singleton infants, the impact of delivery mode on long-term health outcomes in preterm twins remains underexplored. A retrospective cohort study was conducted at a tertiary medical center in Israel from 1991 to 2021, comparing preterm twins vaginally delivered (VD) versus cesarean section, excluding cases with congenital malformations or perinatal deaths. Kaplan-Meier survival curves were used to compare the cumulative incidence, and Cox proportional hazards models were applied to adjust for potential confounders. Four thousand twenty-eight preterm twin offspring were included, with 1703 (42%) VD and 2325 (58%) by CD. Preterm twins delivered by CD had a higher incidence of respiratory morbidities (42% vs. 35% in the VD group, p < 0.001), with an adjusted Hazard Ratio (aHR) of 1.15 (95%CI 1.02-1.30). CD was associated with an increased incidence of neurologic morbidities (22% vs. 17% in the VD group, p < 0.001), with an aHR of 1.16 (95%CI 1.02-1.36). CD was associated with a higher incidence of infectious morbidities (69% vs. 62%, p < 0.001), with an aHR of 1.10 (95%CI 1.01-1.21). Gastrointestinal morbidities were more pronounced in the CD group (29% vs. 25%, p < 0.001), but the multivariable analysis did not reach significance (aHR = 1.10, 95%CI 0.95-1.27). Sub-analyses of elective-uncomplicated deliveries showed consistent results for most morbidities.

Cesarean delivery in preterm twins is associated with long-term respiratory, neurologic, infectious and gastrointestinal morbidities of the offspring. The findings suggest the potential benefits of vaginal over cesarean deliveries regarding offspring long-term health complications.

• Studies on singleton births show that cesarean delivery may increase respiratory, infectious, neurological and gastrointestinal outcomes remains inconsistent across term and preterm deliveries. • Cesarean delivery rates remain high despite recommendations to reduce their frequency, yet data on the association between cesarean delivery and morbidity among twins, particularly in small for gestational age twins, is limited.

• This is the first large-scale study demonstrating that cesarean delivery in preterm twins increases the odds of respiratory, neurologic, infectious and gastrointestinal long-term morbidities up to age 18. • The higher rates of respiratory, neurologic, infectious, and gastrointestinal complications persist even in uncomplicated cesarean deliveries.