SSRI Use During Pregnancy Associated with Autism and Developmental Delays, Higher Risk in Boys

Highest association for ASD was with first trimester exposure, for DD with third trimester exposure.

In the study, researchers from the Johns Hopkins Bloomberg School of Public Health (Baltimore, MD, USA) analyzed data from confirmed ASD and DD cases and population-based controls. Interviews with biological mothers ascertained prenatal SSRI use, maternal mental health history, and sociodemographic information. Findings were similar among mothers with an anxiety or mood disorder history.

The study included 966 mother-child pairs from a population-based case-control study based at the University of California at Davis MIND Institute. The children ranged in ages from 2 to 5 years and were analyzed in 3 groups: children with ASD (n=492), with DD (n=154), and with typical development (TD; n=320).

A majority of the children were boys – 82.5% in the ASD, 65.6% in the DD, and 85.6% in the TD group. While the study included girls, the substantially stronger effect in boys alone suggests possible gender difference in the effect of prenatal SSRI exposure. "We found prenatal SSRI exposure was nearly 3 times as likely in boys with ASD relative to typical development, with the greatest risk when exposure took place during the first trimester,” said Li-Ching Lee, PhD, ScM, psychiatric epidemiologist at the Bloomberg School; “SSRI was also elevated among boys with DD, with the strongest exposure effect in the third trimester.”

Serotonin is critical to early brain development. According to the Centers for Disease Control and Prevention, an estimated 1 in 68 children in the USA is identified with ADS (and almost 5 times more common among boys than girls). One may question whether the increased use of SSRI in recent years is a contributor to the dramatic rise of ASD prevalence.

Regarding treatment, since maternal depression itself carries risks for the fetus: “This research also highlights the challenge for women and their physicians to balance the risks versus the benefits of taking these medications, given that a mother’s underlying mental-health conditions also may pose a risk, both to herself and her child,” said Irva Hertz-Picciotto, PhD, MPH, chief of the Division of Environmental and Occupational Health in the UC Davis Department of Public Health Sciences and researcher at the UC Davis MIND Institute.

The researchers note that large sample studies are needed to investigate the effects in girls with ASD. They acknowledge that limitations of the study also include the difficulty in isolating SSRI effects from those of their indications for use, lack of information on SSRI dosage precluded dose-response analyses, and the relatively small sample of DD children resulted in imprecise estimates of association, which should be viewed with caution.

The study, by Harrington RA et al., was published online ahead of print April 14, 2014, in the journal Pediatrics.

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