Depression is a serious issue for expecting mothers. Left untreated, depression could have implications for a fetus's health. But treating the disease during pregnancy may carry health risks for the developing fetus, which makes an expecting mother's decision whether to take medication a very difficult one. To better understand how antidepressants affect fetuses during pregnancy, scientists studied exposure in mice. They report their findings in the journal ACS Chemical Neuroscience.

In recent years, the number of pregnant women taking antidepressants has been on the rise. Studies have suggested that common antidepressants known as selective-serotonin reuptake inhibitors (SSRIs) could affect the health of these women's children. How they might do this is unclear. For example, pregnancy could affect the metabolism of SSRIs in the body and in turn a fetus's exposure to them. Alexandre Bonnin and colleagues at the Zilkha Neurogenetic Institute (University of Southern California) wanted to gain more insight into how SSRIs are metabolized and travel in mothers and their fetuses.

The researchers administered a widely prescribed SSRI, citalopram, to pregnant mice and tracked what happened to the drug. They found that the medication and its primary metabolite travel quickly to fetuses and their brains.

Also, two hours after administrating the drug, the fetuses had higher concentrations of the drug in their blood than their mothers. In addition, they found important differences in fetal drug exposure depending on the stage of pregnancy. Further work will be needed to see whether SSRIs might act similarly in humans and what effect this exposure might have on fetuses.