53 Long-term neurodevelopmental outcomes among children following forceps, vacuum, and cesarean delivery in the second stage of labour

Abstract Background Opportunities for training in operative vaginal delivery (forceps and vacuum delivery) have declined in Canada over the last two decades along with a concomitant increase in maternal and neonatal trauma following these deliveries. While several studies have demonstrated the acute neonatal morbidity associated with forceps and vacuum delivery in Canada, the long-term consequences of these deliveries, such as neurodevelopmental morbidity in children, remain understudied. Objectives We aimed to quantify the association between mode of delivery in the second stage of labour (forceps, vacuum, sequential instrument, and cesarean delivery) and neurodevelopmental disorders in children, namely, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and intellectual disability (ID). Design/Methods We conducted a population-based, cohort study including all liveborn singletons without a congenital anomaly in British Columbia, Canada (2000-2019). Children were followed from age 1 until they experienced a diagnosis, death, emigration, or study completion, which ever came first. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) compared the incidence of ADHD, ASD, and ID in forceps, vacuum, sequential instrument, and second stage cesarean delivery groups while adjusting for several maternal demographic and clinical factors. We performed a mediation analysis to assess the contribution of severe neonatal birth trauma and birth asphyxia to the association between mode of delivery and each neurodevelopmental disorder. Results Among the 97,529 children included in the study, 8.0% developed ADHD, 2.2% developed ASD, and 0.3% developed ID. Compared with second stage cesarean delivery, children born after sequential instrument use had a 16% higher rate of ADHD (7.9 vs. 6.6 per 1,000 person-years; aHR 1.16, 95% CI 1.03-1.31) while children born with vacuum delivery had a 46% higher rate of ID (0.3 vs. 0.2 per 1,000 person-years; aHR 1.46, 95% CI 1.08-1.97). No associations between mode of delivery in the second stage of labour and ASD were found. Birth trauma and asphyxia did not considerably mediate the relationship between mode of delivery in the second stage of labour and ADHD and ID, respectively. Conclusion Compared with second stage cesarean delivery, sequential instrument use was associated with an increased risk of ADHD while vacuum delivery was associated with an increased risk of ID. Investigations into the causal relationships underlying these associations are warranted to assist pregnant individuals and their care providers in making informed decisions about mode of delivery options in the second stage of labour.