Synthetic ovulation stimulant. It inhibits hypothalamic estrogen receptors, which in turn stimulates the release of FSH, estradiol and LH. It has initially anti-estrogenic and then estrogenic effects.Indicated to induce ovulation in infertility treatment and polycystic ovary syndrome (Hossein 2016, AEMPS 2016, Sanofi 2012, López 2004, Sheehan 2004, Kousta 1997).Increased risk of multiple pregnancy. Administered orally, a daily dose for 5 days, maximum 3 menstrual cycles. Since the last update, we have not found published data on its excretion in breast milk. Its high volume of distribution makes the transfer to milk in significant quantities unlikely, but its long half-life could facilitate it. Adverse effects are infrequent and temporary at usual doses; they occur in high doses and for prolonged periods such as those used in research studies (AEMPS 2016, Sanofi 2012). Studies on the effects on prolactin and milk production are scarce, out of date and contradictory, for while for some authors clomiphene decreases prolactin plasma levels, inhibiting breastfeeding when administered during the first week postpartum (Weinstein 1976, Kalir 1975), for others it has no effect on prolactin nor does it inhibit breastfeeding (Canales 1977). In any case, when breastfeeding is well established, prolactin levels do not correlate with milk production. This would be the case in an infertility treatment. It is not advisable to take it during the first weeks of the postpartum period due to the risk of decreased milk production. In infertility treatment, the possible anovulatory effect of frequent on demand breastfeeding should be taken into account. See below the information of these related products: