LAUSR

ABSTRACT Selective serotonin‐reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants during pregnancy. The human placenta is a highly specialized organ supporting normal growth and development of the fetus. Therefore, this study aims to analyze the effects of SSRIs on villous cytotrophoblasts cells, using BeWo cells and human placental trophoblast cells in primary culture. The SSRIs fluoxetine and its metabolite norfluoxetine, sertraline and venlafaxine did not affect BeWo cell proliferation and viability, nor the percentage of M30‐positive (apoptotic) primary trophoblast cells. None of the SSRIs affected basal or forskolin‐stimulated BeWo cell fusion, whereas sertraline and venlafaxine increased the fusion of primary villous trophoblasts. Sertraline and venlafaxine also modified human chorionic gonadotropin beta (&bgr;‐hCG) secretion by BeWo cells, whereas none of the SSRIs affected &bgr;‐hCG secretion in primary trophoblasts. Norfluoxetine increased CGB (chorionic gonadotropin beta) and GJA1 (gap junction protein alpha 1) levels of gene expression (biomarkers of syncytialization) in BeWo cells, whereas in primary trophoblasts none of the SSRIs tested affected the expression of these genes. This study shows that SSRIs affect villous trophoblast syncytialization in a structure‐ and concentration‐dependent manner and suggests that certain SSRIs may compromise placental health. In addition, it highlights the importance of using primary trophoblast cells instead of “trophoblast ‐like” cell lines to assess the effects of medications on human villous trophoblast function. HIGHLIGHTSSSRIs affect villous trophoblast syncytialization in a structure‐ and concentration‐dependent manner.SSRIs affect syncytialization differently in BeWo cells than primary villous trophoblasts.Sertraline increases morphological differentiation of primary villous trophoblast.Sertraline at 10&mgr;M affects BeWo proliferation.