Researchers from the Bloomberg School of Public Health found that early prenatal exposure to selective serotonin reuptake inhibitors (SSRIs) — commonly prescribed for depression, anxiety, and other disorders — increased the risk for ASD three-fold.
Common SSRIs include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil, Pexeva), and sertraline (Zoloft).
The study of 1,000 mother-child pairs is published in the online edition of Pediatrics. In the study, investigators analyzed data from large samples of ASD and DD cases, and population-based controls.
Importantly, researchers used a uniform protocol to confirm ASD and DD diagnoses by trained clinicians using validated standardized instruments.
The study included 966 mother-child pairs from the Childhood Autism Risks from Genetics and the Environment (CHARGE) Study, a population-based case-control study based at the University of California at Davis’ MIND Institute.
The researchers broke the data into three groups: Those diagnosed with autism spectrum disorder (ASD), those with developmental delays (DD), and those with typical development (TD).
The children ranged in ages two to five. A majority of the children were boys — 82.5 percent in the ASD group were boys, 65.6 percent in the DD group were boys, and 85.6 percent in the TD were boys.
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 three 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, Ph.D., Sc.M.
“SSRI was also elevated among boys with DD, with the strongest exposure effect in the third trimester.”
“Serotonin is critical to early brain development; thus, exposure during pregnancy to anything that influences serotonin levels can have potential effect on birth and developmental outcomes,” said the researchers.
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In the U.S., the prevalence of ADS continues to rise. According to the Centers for Disease Control and Prevention, an estimated one in 68 children in the U.S. is identified with ADS, and it is almost five 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.
“This study provides further evidence that in some children, prenatal exposure to SSRIs may influence their risk for developing an autism spectrum disorder,” said Irva Hertz-Picciotto, Ph.D., M.P.H.
“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.”
Regarding treatment, the authors note that maternal depression itself carries risks for the fetus, and the benefits of using SSRI during pregnancy should be considered carefully against the potential harm.
The researchers also note that large sample studies are needed to investigate the effects in girls with ASD.
Limitations of the study acknowledged 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.
Source: Johns Hopkins