Prenatal exposure to medications frequently prescribed to treat depression, anxiety and other mental-health disorders, is associated with a higher incidence of autism spectrum disorder and developmental delays in male children, a study of nearly 1,000 mother-child pairs has found.
“This study provides further evidence that in some children, prenatal exposure to (selective serotonin reuptake inhibitors) may influence their risk for developing an autism spectrum disorder,” said Professor Irva Hertz-Picciotto, chief of the division of environmental and occupational health.
“It also highlights the challenge for women and their physicians, to balance the risks vs. benefits from taking these medications, given that a mother’s underlying mental-health conditions may also pose a risk to both herself and her child.”
Published online Monday in the journal Pediatrics, the study involved 966 mother-child pairs from the Childhood Autism Risks from Genetics and the Environment Study: a population-based, case-control study at the UC Davis MIND Institute led by Hertz-Picciotto.
The study participants included the mothers of children with autism spectrum disorder, developmental delay and those with typical development. The children ranged in age from 2 to 5. A majority of the children in each category were boys.
While the study included girls, the substantially stronger effect in boys suggests a possible gender difference in the effect of prenatal SSRI exposure, the authors said.
“We found prenatal SSRI exposure was nearly three times as likely in boys with (autism spectrum disorder) relative to those with typical development, with the greatest risk occurring when exposure took place during the first trimester,” said Li-Ching Lee, psychiatric epidemiologist in the Bloomberg School’s Department of Epidemiology.
“SSRIs also were elevated among boys with developmental delay, with the strongest exposure effect in the third trimester.”
According to statistics recently released by the U.S. Centers for Disease Control and Prevention, an estimated 1 in 68 U.S. children are diagnosed with autism. The condition is almost five times more commonplace among boys than girls.
The researchers caution that while there has been a co-occurring increase in the use of SSRIs, it likely is not a significant contributor to the increase in the prevalence of autism.
“Because of low rates of SSRI use during pregnancy and possible co-existing factors influencing susceptibility to (autism spectrum disorder) from SSRI exposure, any contribution of these medications to the increase in the prevalence of ASDs likely is minimal,” Lee said.
Maternal depression carries its own risks to the fetus, so that the benefits of using SSRIs during pregnancy should be weighed carefully against any potential harm, the authors noted.
They also noted that large sample studies are needed to investigate the effects in girls with autism.
The study’s limitations include the difficulty of isolating SSRIs’ effects from those of their indications for use; lack of information on SSRI dosage precluding dose-response analyses, and the relatively small sample of children with developmental delay resulting in imprecise estimates of association.
— UC Davis News