Importance
Prenatal antidepressant exposure has been associated with adverse outcomes. Previous studies, however, may not have adequately accounted for confounding.
Objective
To evaluate alternative hypotheses for associations between first-trimester antidepressant exposure and birth and neurodevelopmental problems.
Design, Setting, and Participants
This retrospective cohort study included Swedish offspring born between 1996 and 2012 and followed through 2013 or censored by death or emigration. Analyses controlling for pregnancy, maternal, and paternal covariates, as well as sibling comparisons, timing of exposure comparisons, and paternal comparisons, were used to examine the associations.
Exposures
Maternal self-reported first-trimester antidepressant use and first-trimester antidepressant dispensations.
Main Outcomes and Measures
Preterm birth (< 37 gestational weeks), small for gestation age (birth weight < 2 SDs below the mean for gestational age), and first inpatient or outpatient clinical diagnosis of autism spectrum disorder and attention-deficit/hyperactivity disorder in offspring.
Results
Among 1,580,629 offspring (mean gestational age 279 days; 48.6% female; 1.4% [n = 22,544] with maternal first-trimester self-reported antidepressant use) born to 943,776 mothers (mean age at childbirth 30 years), 7.0% of exposed vs. 4.8% of unexposed offspring were preterm, 2.5% of exposed vs. 2.2% of unexposed were small for gestational age, 5.3% of exposed vs. 2.1% of unexposed were diagnosed with autism spectrum disorder by age 15, and 12.6% of exposed vs. 5.5% of unexposed were diagnosed by attention-deficit/hyperactivity disorder by age 15. At the population level, first-trimester exposure was associated with all outcomes, compared with unexposed offspring (preterm birth: OR = 1.5, 95% CI, [1.4, 1.6]; small for gestational age: OR = 1.2, 95% CI, [1.1, 1.3]; autism spectrum disorder: HR = 2.0, 95% CI, [1.8, 2.3]; attention-deficit/hyperactivity disorder: HR = 2.2, 95% CI, [2.0, 2.4]). However, in models that compared siblings while adjusting for pregnancy, maternal, and paternal traits, first-trimester antidepressant exposure was associated with preterm birth (OR = 1.3, 95% CI [1.2, 1.5]) but not with small for gestational age (OR = 1.0, 95% CI [0.8, 1.3]), autism spectrum disorder (HR = 0.8, 95% CI [0.6, 1.1]), or attention-deficit/hyperactivity disorder (HR = 1.0, 95% CI [0.8, 1.3]). Results from analyses assessing associations with maternal dispensations before pregnancy and paternal first-trimester dispensations were consistent with findings from the sibling comparisons.
Conclusion and Relevance
Among offspring born in Sweden, after accounting for confounding factors, first-trimester antidepressant exposure, compared to no exposure, was associated with a small increased risk of preterm birth but no increased risk of small for gestational age, autism spectrum disorder, or attention-deficit/hyperactivity disorder.