Vacuum-assisted delivery (VAD) is frequently employed in obstetric practice to address fetal distress or prolonged labor but raises concerns about possible long-term neurodevelopmental effects, especially when performed at mid or low fetal head stations. Although mid/low VAD procedures may increase neonatal complications, evidence regarding enduring neurodevelopmental outcomes remains limited, particularly distinguishing between outlet and mid/low VAD. This research aims to fill gaps in knowledge by examining both immediate neonatal outcomes and long-term neurodevelopmental sequelae following VAD in a comprehensive national cohort.
This population-based cohort study was conducted in Sweden, leveraging nationwide health registers linked by unique personal identification numbers to enable robust long-term follow-up. Data sources included the Swedish Medical Birth Register, National Patient Register, Prescribed Drug Register, and socio-demographic databases, encompassing virtually all hospital births and related medical data. These high-quality registers ensure comprehensive capture of exposures, outcomes, and covariates from 1997 through 2021.
The cohort comprised all singleton, term-born (≥37 weeks gestation) infants delivered to first-time mothers between 1997 and 2014, excluding breech presentations, forceps deliveries, congenital malformations, and preterm births. VAD cases were stratified into outlet and mid/low fetal head stations based on procedural codes. Two reference groups were included: emergency cesarean delivery (ECD) and spontaneous vaginal delivery, facilitating comparisons across delivery modalities.
Neonatal outcomes of interest encompassed clinically significant complications such as intracranial hemorrhages (traumatic and non-traumatic), subgaleal hematoma, meconium aspiration, respiratory distress, seizures, and ischemic stroke, identified using ICD-10 codes. Long-term neurodevelopmental outcomes included attention deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), cerebral palsy (CP), epilepsy (EP), and intellectual disability (ID), operationalized as at least two diagnoses or, for ADHD, diagnosis plus prescription of relevant medication. Follow-up began at disorder-specific ages and extended through 2021, spanning 7 to 24 years.
Multivariable logistic regression estimated neonatal outcome odds ratios (ORs), while Cox proportional hazards models assessed long-term neurodevelopmental hazard ratios (HRs), adjusted for maternal age, body mass index, smoking, diabetes, gestational complications, maternal education, psychiatric history, child’s birth year, and chorioamnionitis. Analyses were stratified by child sex and fetal head station, and sensitivity analyses addressed perinatal asphyxia, birthweight, gestational age, and period effects.
Compared to emergency cesarean delivery, mid/low VAD was associated with significantly higher odds of neonatal intracranial hemorrhage (adjusted ORs up to 7.2 for traumatic hemorrhage), subgaleal hematoma, and neonatal seizures. Conversely, mid/low VAD cases showed reduced odds of meconium aspiration. Outlet VAD demonstrated outcomes comparable to spontaneous vaginal delivery, with generally lower risks of adverse neonatal events relative to ECD.
In follow-up reaching a median of 13 to 14 years, children born via mid/low VAD did not exhibit increased risk for ADHD, ASD, CP, or epilepsy relative to emergency cesarean delivery. Notably, mid/low VAD was associated with a modestly reduced risk of intellectual disability (adjusted HR 0.80). Outlet VAD, similar to spontaneous vaginal delivery, showed no increased risks of long-term neurodevelopmental disorders and, in some comparisons, lower risks than ECD.
Strengths include the large, nationwide cohort, detailed registry data, long duration of follow-up, and rigorous statistical adjustment. However, the study lacked information on specific clinical indications for VAD or ECD and did not distinguish cesarean timing in labor stages, complicating causal interpretation. These limitations underline the need for cautious interpretation when comparing delivery modes, recognizing differing clinical contexts.
This study provides reassuring evidence that appropriately conducted vacuum-assisted deliveries, including mid/low VAD, are not associated with increased long-term neurodevelopmental disorders despite an elevated risk of certain neonatal complications. Outlet VAD appears particularly safe. These findings support the continued use of VAD as a valuable obstetric option while highlighting the importance of careful clinical judgment. Ultimately, results inform clinicians and policymakers about the long-term safety profile of VAD and help fill knowledge gaps to optimize delivery practices.