Normal pregnancy is associated with high circulating levels of total testosterone explained by an increment of the synthesis of testosterone-estradiol-binding globulin (TeBG), and an increase in plasma free-testosterone and androstenedione levels. Protection mechanisms against maternal and fetal virilization conterbalance this biological hyperandrogenism. However, these mechanisms of protection may be overtaken leading to a maternal virilization during pregnancy. Acne, temporal balding, clitoromegaly and hirsutism could be observed. The most important point is to evaluate the risk of virilization of a female fetus. Earlier the hyperandrogenism occurs during pregnancy, higher is the risk of fetal virilization. The first step consists to identify a gestational exposition to androgen, the second to find an organic etiology. The most common etiologies include ovarian luteomas and theca-lutein-cysts. Others ovarian diseases (arrhenoblastomas, Krukenberg tumors and polycystic ovary syndrome) and adrenal causes are much more rare. Unfortunately, there is no treatment available during pregnancy.