Cohort

Cohort

1. Variables

   • Maternal use of acetaminophen during pregnancy
   • Risk of autism spectrum disorders in childhood

2. Patients

   • Live born children whose mothers participated in all three telephone interviews which information on prenatal acetaminophen use was collected (at approximately 12th and 30th gestational week and 6 months after birth).
   • Excluded
     • Pregnancies ending in miscarriages, nonsingleton births, mothers who emigrated or died, unknown birth outcomes, missing birth dates, or mothers who missed one or more interviews.

3. Confusing variables

4. Statistical tests

   • Statistical analyses were performed using SAS 9.2 (SAS Institute Inc., Cary, NC, USA). They used Cox proportional hazards regression models to estimate hazard ratios (HR) and 95% confidence intervals (CIs) for ASD.

5. Sample size

   • 64,322 live born children

6. Biases

   • Women who used acetaminophen repeatedly during pregnancy are likely to have suffered pain, but pain is not known to be a strong risk factor for ASD
   • There could be other unmeasured characteristics of women who took acetaminophen for prolonged periods during pregnancy that we were unable to account for

7. Conflicts of interest

   • All authors have no conflicts of interest to disclose.

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