BACKGROUND AND PURPOSE:

• Recent studies suggest a link between cesarean delivery and attention-deficit/hyperactivity disorder (ADHD) or autism-spectrum disorder (ASD)
  • Studies did not control for cesarean indications or familial confounding
• Zhang et al. (JAMA Network Open, 2021) examined the association between cesarean delivery and neurodevelopmental/psychiatric disorders in offspring

METHODS:

• Swedish register-based cohort study
• Participants
  • Term-birth | Singleton
  • Born between January 1, 1990 and December 31, 2003
  • Follow up through December 31, 2013
• Exposures
  • Birth by cesarean (planned or intrapartum)
• Study design
  • All included individuals were linked to their full siblings, maternal and paternal half siblings, and maternal full cousins
  • Neurodevelopmental disorders
    • ADHD | ASD | Intellectual disability | Tic disorders | Communication disorders | Learning disorders | Any neurodevelopmental disorder
  • Psychiatric disorders
    • Anxiety disorders | Obsessive-compulsive disorder | Depressive disorders | Eating disorders | Bipolar disorders | Psychotic disorders | Any psychiatric disorder
• Primary outcomes
  • Registered diagnoses of neurodevelopmental disorders
  • Diagnoses of psychiatric disorders

RESULTS:

• 1,179,341 individuals
  • Vaginal delivery: 1,048,838
    • Mean age at follow up: 17.7 years
  • Delivered via planned cesarean: 59,514
    • Mean age at follow up: 16.6 years
  • Delivered vis intrapartum cesarean: 70,989
    • Mean age at follow up 16.8 years

Not Adjusted for Familial Confounding

• Compared with vaginal delivery, cesarean delivery was associated with higher risk for
  • Any neurodevelopmental disorder | ADHD | Intellectual disability
• Only planned CD was associated with a higher risk for
  • ASD | Communication disorders | Learning disorders

Adjusted or Familial Confounding

• The associations between cesarean delivery and any neurodevelopmental disorder, ADHD, ASD, and intellectual disability
  • Attenuated in full cousins and paternal half siblings
  • Further attenuated (became nonsignificant) in maternal half siblings and full siblings
  • Risk of any neurodevelopmental disorder in full siblings
    • Planned cesarean: HR, 0.93 (95% CI, 0.81 to 1.06)
    • Intrapartum cesarean: HR 1.07 (95% CI, 0.96 to 1.21)

CONCLUSION:

• The association between cesarean delivery and increased risk for neurodevelopmental disorders found in previous studies is likely due to unmeasured familial confounding, not the procedure itself
• The authors conclude

…observed associations attenuated to the null after adjusting for familial factors

Overall, the results do not suggest a causal association between CD and neurodevelopmental and psychiatric disorders

Learn More – Primary Sources:

Assessment of Cesarean Delivery and Neurodevelopmental and Psychiatric Disorders in the Children of a Population-Based Swedish Birth Cohort

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