Women who need treatment for depression or anxiety while pregnant may find reassurance in a new study. The new research found no increased risk of autism associated with using antidepressant medication during pregnancy.
The study’s key findings include:
Use of selective serotonin reuptake inhibitors (SSRIs) in pregnancy was not independently associated with greater risk of autism in children.
In women who had taken SSRI antidepressants during one pregnancy and not in another, there was no difference in autism risk between the siblings.
There was no difference in autism risk between children whose mothers took SSRI antidepressants in pregnancy, and children whose mothers stopped taking antidepressants shortly before pregnancy.
The study was published in JAMA on April 18, 2017, and included 35,906 births in Ontario from 2002 to 2010. The results may help women make decisions about treatment for depression or anxiety while pregnant.
“There is a great deal of pressure on women not to take medications during pregnancy,” says study author Dr. Simone Vigod, a psychiatrist at Women’s College Hospital. She notes that while it is important to weigh the risks and benefits of any medication, it’s also important to consider the effects of not treating a condition.
“I think people fail to consider that untreated mental illness in pregnancy can have serious impact,” she says.
Some of the risks of untreated depression or anxiety in pregnancy include:
Effects on the baby either directly through the illness itself, or through symptoms like poor sleep or poor nutrition that can affect the fetus.
The longer mental illness is untreated, the harder it can be to treat, and the higher the risk of chronic mental illness.
It may have a negative impact on the woman’s relationships with her partner and her other children.
The biggest risk factor for postpartum mental illness is untreated mental illness during pregnancy.
The study counters earlier research that suggested a possible link between antidepressant use in pregnancy and autism risk in children. Dr. Vigod says the new research used a more detailed approach to ensure an accurate comparison.
“The problem with those earlier studies is that for women who take antidepressant medications during pregnancy, there’s some reason why they’re taking the medication: they suffer from depression or anxiety,” she says.
That alone means there may be differences between these women and those not taking antidepressants, so a simple comparison of autism rates may be very misleading.
“It’s possible that depression or anxiety could have a direct impact on fetal brain development through physiological mechanisms,” Dr. Vigod explains. “It has been shown that depression and autism have a shared genetic predisposition. So if a woman has depression or anxiety, even if she’s not symptomatic in pregnancy, her child might have a higher risk of developing autism just by shared genetics.”
The symptoms of anxiety and depression may also have an effect on pregnancy.
“For example, if a woman has depression or anxiety she may also be more likely to not have as good nutrition, she might not be sleeping as well, she might be more likely to use alcohol or drugs, or she might have other medical conditions.”
All of those issues make it hard to isolate the possible effects of antidepressant medications from the potential effects of mental illness.
“We set out to try to balance out the groups to better understand whether this was a causal relationship or not,” Dr. Vigod says.
More accurate comparisons
To do that, she and her research colleagues used a special method called high dimensional propensity score (HDPS) analysis. This method looks for thousands of different types of health claims, from diagnoses and prescriptions to hospital stays and emergency department visits. The HDPS score of the women who took antidepressants in pregnancy was then matched to a more balanced group of women with a similar score, but who did not take antidepressants in pregnancy.
“When we did that in our main analysis, suddenly there was no longer an association between antidepressant exposure and autism,” Dr. Vigod says.
The researchers then looked at some of the results more closely.
First, they identified women who had at least two children, and who had taken antidepressants in at least one pregnancy and not in another. They compared autism risk in the siblings, and found no difference between the children exposed to antidepressants and those who weren’t.
Then, they compared the children of women who took antidepressants in pregnancy to the children of women who stopped taking antidepressants shortly before pregnancy.
“Again, in that analysis those children were not significantly different in their autism risk,” Dr. Vigod says.
These additional comparisons support the main study result: the findings showed no evidence that antidepressants in pregnancy are independently related to autism risk in children.
“What that suggests is that while kids whose moms took antidepressants may be at higher risk of autism, it’s probably not because of the antidepressants,” Dr. Vigod says.
“While we can never say that any medication exposure has zero risk, in general these medications are relatively low risk, so if women require them for their psychiatric stability, they can feel reassured that they are not unduly putting their children at risk.”
The study results may also be reassuring to mothers of children with autism who may have used antidepressants during pregnancy.
“These results may also be reassuring for those parents, to say that your child having autism isn’t a result of a decision you made,” Dr. Vigod says. “I think that can be very helpful, too.”