Neurodevelopmental disorders in children commonly include intellectual disability (ID) occurring in about 0.4 to 1%, attention-deficit/hyperactivity disorder (ADHD) with a prevalence of 5 to 7%, and autism spectrum disorder (ASD) affecting 1 to 2%. These conditions have multifactorial causes involving both genetic and environmental influences. Longitudinal studies are needed to identify potentially modifiable risk factors. The mode of delivery has been explored as one such factor, with some studies reporting higher risks of ID, ADHD, and ASD after operative vaginal delivery or cesarean compared to spontaneous vaginal delivery (SVD). However, these findings are limited by broad comparisons and confounding. These issues were well explained in a recent study published in the JAMA Network Open, aimed to assess the relationship between the manner of delivery during the second stage of labor and risks of ID, ADHD, and ASD.
In this population-based retrospective study, data of singleton term infants born at 37-42 weeks during the second stage of labor were collected from the British Columbia Perinatal Data Registry from April 1, 2000, to December 31, 2019. Delivery modes were second-stage cesarean delivery (SSCD), forceps, SVD, sequential instruments, and vacuum. Outcomes included identified diagnosis of ID, ASD, and ADHD after one year of age through March 31, 2022, using validated ICD-10 and ICD-9 algorithms. Analyses were adjusted for pregnancy-related confounders, characteristics of the mother, and relevant clinical factors. Â
A total of 504,380 children (female = 251,124; male = 253,256) with a maternal history of psychiatric or neurodevelopmental disorders were included in this study. Among them, 4.7% were born by SSCD (n = 23,140), 9.2% by vacuum delivery (n = 46,493), 0.6% by sequential instrument delivery (n = 3,009), 4.6% by forceps delivery (n = 23,140), and 80.9% by SVD (n = 407,792).
Results showed that ADHD occurred at a rate of 6.6/1000 person-years with 7,693 cases (95% confidence interval [CI]: 6.5-6.7; median follow-up = 11.6 years), ID at 0.3/1000 with 323 cases (95% CI: 0.2-0.3, median follow-up = 12.6 years), and ASD at 1.8/1000 with 131 cases (95% CI: 1.7-1.8, median follow-up = 12.6 years). ADHD rates were highest after sequential instrument delivery at 7.9/1000 person-years (95% CI: 7.1-8.8), followed by vacuum at 6.7 (95% CI: 6.5–6.9), SSCD at 6.6 (95% CI: 6.3-6.9), and forceps at 6.2 (95% CI: 5.9-6.5). ASD rates were highest after SSCD at 2/1000 person-years (95% CI: 1.9-2.2), whereas ID rates were similar across all delivery modes, ranging from 0.2 to 0.3/1000 person-years.
After adjustment, sequential instrument delivery was strongly associated with a higher rate of ADHD, with an adjusted hazard ratio (AHR) of 1.13 (95% CI: 1.00-1.28), and vacuum delivery with a higher ID rate, with an AHR of 1.53 (95% CI: 1.12-2.10). There was no strong association observed between modes of delivery and ASD.
This study’s limitations include low sensitivity of ASD diagnosis, survival bias, potential residual confounding from unmeasured sociodemographic and socioeconomic factors, practitioner preferences, incomplete data on smoking and body mass index (BMI), and unmeasured comorbidities.
In conclusion, this study demonstrates that second-stage labor interventions are generally safe. Observed associations with neurodevelopmental disorders are likely attributable to underlying clinical indications rather than the delivery mode itself. Future research should compare patients with similar labor characteristics to better clarify the true impact of delivery mode on childhood neurodevelopmental outcomes.
Reference: Rajasingham M, Lisonkova S, Razaz N, Muraca GM. Long-Term Neurodevelopmental Outcomes After Forceps, Vacuum, and Second-Stage Cesarean Delivery. JAMA Netw Open. 2026;9(1):e2556637. doi:10.1001/jamanetworkopen.2025.56637
