UCLA

Selective serotonin reuptake inhibitors (SSRIs) are used as first-line treatments by up to 10% of pregnant women suffering from major depression. However, the effects of prenatal SSRI use on fetal development are still largely unknown. Serotonin plays crucial roles in the early development of the fetal brain, and the fetus depends on a maternal source of serotonin. In humans, 90% of serotonin synthesis occurs in the gut, promoted by specific microbiota. In the present study, we used a pregnant mouse model to assess for changes in the maternal microbiome, after early prenatal fluoxetine gavage. We examined the fetal brain for changes in the development of the dorsal raphe nucleus, as well as its axonal projections to the prefrontal cortex. Our results suggest that prenatal SSRI use does not result in a significant shift in maternal microbiome, and has no direct effect on the development of the endogenous fetal serotonergic system.