Women with symptoms of severe depression have a decreased chance of becoming pregnant, according to a new study.

Researchers from the Boston University Schools of Public Health and Medicine say they also found that using psychotropic medications does not appear to harm fertility.

The study, published in the American Journal of Obstetrics and Gynecology, found a 38 percent decrease in the average probability of conception in a given menstrual cycle among women who reported severe depressive symptoms, compared to those with no or low symptoms.

The results were similar, regardless of whether the women were on psychotropic medications, the researchers noted.

Despite associations in previous studies between infertility and the use of antidepressants, antipsychotics, or mood stabilizers among already infertile women, “current use of psychotropic medications did not appear to harm the probability of conception,” said lead author Yael Nillni, an assistant professor of psychiatry at the School of Medicine and a researcher with the National Center for PTSD, Women’s Health Sciences Division of the VA Boston Healthcare System.

“Our findings suggest that moderate to severe depressive symptoms, regardless of current psychotropic medication treatment, may delay conception.”

Data for the study came from more than 2,100 women between the ages of 21 and 45 enrolled in a Boston University-led study known as PRESTO (Pregnancy Study Online) that is looking at factors influencing fertility.

The women were asked to report their current depressive symptoms and psychotropic medication use, among many other factors. Overall, 22 percent reported a clinical diagnosis of depression in their medical histories, while 17.2 percent were former users of psychotropic medication, and 10.3 percent were current users of psychotropic drugs, the researchers reported.

Among the study’s secondary findings was that current use of benzodiazepines — sedatives used to treat anxiety and other disorders — was associated with a decrease in fecundability or the ability to conceive.

The study also found that women who were formerly treated with a class of antidepressants known as SSRIs (selective serotonin reuptake inhibitors) had improved chances of conception, regardless of the severity of the depressive symptoms.

The researchers speculated that former SSRI users could experience some long-term psychological or neurobiological benefits from past treatment that influence fertility. However, the numbers of individual classes of medications were small, and further study is needed, they said.

Although the study does not answer why women with more depressive symptoms may take longer to become pregnant, the researchers noted several potential areas for future study. For example, they note that depression has been associated with dysregulation of the hypothalamic-pituitary-adrenal axis, which may influence the menstrual cycle and affect the ability to conceive.

An estimated 10 to 15 percent of couples in the U.S. experience infertility. Past research has shown that women have a higher prevalence of depressive and anxiety disorders during their childbearing years than during other times of life.

Source: Boston University Medical Center