Long-term neurodevelopmental outcomes after vacuum-assisted delivery: A population-based cohort study

BACKGROUND: Vacuum-assisted delivery (VAD) is widely used in obstetric care, yet concerns remain regarding potential long-term neurodevelopmental sequelae in offspring, particularly after procedures performed at higher fetal head stations. Evidence on long-term outcomes after VAD remains limited. Given the safety concerns surrounding VAD, we investigated neonatal and long-term neurodevelopmental outcomes after VAD stratified by fetal head station, using emergency cesarean delivery (ECD) and spontaneous vaginal delivery as reference groups. METHODS AND FINDINGS: In this population-based cohort study, we obtained data from nationwide health registers and included all singleton births to primiparous women in Sweden between 1997 and 2014, with follow-up through December 31, 2021. Differences in neonatal outcomes across delivery modes were estimated using multivariable logistic regression models to obtain odds ratios (ORs). All children were followed longitudinally for adverse long-term neurodevelopmental outcomes-a diagnosis of attention deficit/hyperactivity disorder [ADHD], autism spectrum disorder [ASD], cerebral palsy [CP], epilepsy [EP], or intellectual disability [ID]. Rates of long-term outcomes were compared using multivariable Cox regression models to obtain hazard ratios (HRs). All analyses were stratified by child sex. Analyses of neonatal outcomes were adjusted for maternal age, body mass index (BMI), gestational age, pre-eclampsia, gestational diabetes, and diabetes mellitus type I/II. Long-term analyses were additionally adjusted for smoking status, child's birth year, chorioamnionitis, maternal education level, and maternal psychiatric comorbidity. Among 630,985 term singleton births, median follow-up was 13-14 years. Compared with ECD, mid/low VAD was associated with increased odds of neonatal intracranial hemorrhage (traumatic aOR 7.20, 95% CI [2.97, 17.45]; non-traumatic aOR 3.65, 95% CI [2.41, 5.52]; subgaleal hematoma aOR 3.35, 95% CI [2.68, 4.20]; and neonatal seizures aOR 1.85, 95% CI [1.52, 2.26]), but with lower odds of meconium aspiration (aOR 0.53, 95% CI [0.42, 0.67]). In long-term follow-up, mid/low VAD showed no increased risks for ADHD, ASD, CP, or epilepsy, and a reduced risk of intellectual disability (aHR 0.80, 95% CI [0.67, 0.96]) as compared with ECD. Outlet VAD-similar to spontaneous vaginal delivery-was associated with lower risks of adverse neonatal and long-term neurodevelopmental outcomes compared with ECD. The main limitations of this study were the lack of information on the indication for intervention and whether emergency cesarean deliveries were performed in the first or second stage of labor. CONCLUSIONS: In this nationwide cohort, mid/low VAD was associated with higher neonatal morbidity but no increased risk of long-term neurodevelopmental disorders. Outlet VAD showed no signal of adverse long-term neurodevelopmental outcomes. These findings provide reassuring evidence regarding the long-term safety of VAD when performed appropriately and help address an important knowledge gap regarding long-term outcomes after VAD. However, comparisons between delivery modes should be interpreted cautiously, as the clinical circumstances leading to VAD and ECD differ and are incompletely captured in register data. The findings should therefore not be interpreted as evidence to guide acute choice of delivery mode.