Last month, a group of California researchers reported an increased risk of autism among babies whose mothers took a certain catergory of antidepressant medications–selective serotonin reuptake inhibitors (SSRIs)—during the first trimester of pregnancy. You may know these drugs by such brand names as Prozac, Effexor, Paxil, and Celexa.
So what do these results mean for pregnant women? First, caution is needed before rushing to judgment. The study was relatively small, and the increase in the risk of autism was modest. So more study is clearly needed to confirm the link and clarify how great a risk, if any, is associated with a mother using this type of antidepressant during pregnancy.
Further caution is needed because the effects of a mother’s anxiety and depression during pregnancy and early infancy are well known. In fact, it’s not clear whether the autism risk associated with taking antidepressants during pregnancy is, in fact, related to the women’s depression rather than the drugs themselves.
For these reason, many doctors have argued that the benefits of SSRIs outweigh concerns about risks that SSRI exposure may pose to a fetus or infant during pregnancy and nursing. Clearly, more research is needed.
Beyond SSRIs, researchers have looked at several other medications to see if their use during pregnancy increases the risk that a baby will go on to develop autism. Among the most thoroughly researched is the anti-seizure medication valproic acid (U.S. brand name Depakote). Studies show that, as a group, children whose mothers take valproic acid during their first trimester of pregnancy are more likely to develop an autism spectrum disorder (ASD) than are children who are not exposed.
Autism Speaks has supported research into how valproic acid might contribute to the development of ASDs. Through the study of donated brain tissue, for example, we have learned that individuals with autism share some “neuropathologies,” or altered brain features, with those who were exposed to valproic acid before birth. In addition, several studies show that exposure to valproic acid during critical periods of brain development can produce autism-like behaviors in animal models.
So the good news is that our research has deepened understanding about how valproic acid during pregnancy can contribute to the development of ASDs. The bad news is that it can be quite dangerous for women with epilepsy to stop taking this medication during pregnancy—owing to their increased risk of seizures. As a result, such decisions should be made carefully with a physician can discuss alternative drugs.
Findings are still emerging with other medications given during pregnancy. For instance, relatively small studies (such as this one) suggest an increased risk for ASD in babies whose mothers were given the medication terbutaline to stop premature labor. Another small study suggested increased risk of autism related to women taking high doses of the anti-ulcer drug misoprostol early in pregnancy. (This drug is also used to induce labor later in pregnancy.) But in many cases, such preliminary research has yet to move past the “interesting” stage to reach enough certainty to change medical practices.
Other, larger studies hint at an increased risk of autism in the babies of women who take certain broad classes of medications such as antipsychotics or mood stabilizers during pregnancy. Still the question remains: Is the autism risk due to the medications or to the underlying medical conditions that the drugs are being used to treat?
Beyond medications, studies have revealed a number of other pregnancy complications and events that appear to contribute to the risk that a baby will go on to develop autism. These include the pregnant mother’s exposure to toxic chemicals, infections such as flu, and her diet and nutrition at the time of conception as well as during pregnancy.
Autism Speaks continues to fund a number of important studies looking at autism risk factors during pregnancy. If you have at least one child already diagnosed with an ASD, find out more about participating in the EARLI study (link at left) before or at the start of your next pregnancy. Or consider enrolling your child and family in the CHARGE study, which looks at risk factors before, during, and after your child’s birth.
We will be continuing to update you on the science as it emerges. If you have any concerns about the medications you are taking during pregnancy, please discuss them with your doctor. For more resources, we also recommend the Organization of Teratology Information Specialists.