RESUMEN
<p><b>OBJECTIVE</b>To investigate the effects of oral contraceptive pretreatment (OCP) in patients with polycystic ovarian syndrome (PCOS) undergoing controlled ovarian hyperstimulation for IVF-ET.</p><p><b>METHODS</b>We randomly divided 85 patients with P-COS undergoing IVF-ET into an OCP (n = 53) and a control group (n = 32), the former received OCP, while the latter did not before the cycle. We retrospectively analyzed the data of the patients for the ovulation promoting effect of OCP and its influence on the incidence of ovarian hyperstimulation syndrome (OHSS) and outcomes of IVF-ET.</p><p><b>RESULTS</b>Compared with the control group, OCP significantly reduced the formation of ovarian cyst (P < 0.05), remarkably increased the duration of gonadotropin stimulation and consumption (P < 0.01) , and markedly raised the percentage of mature ova (87.92% vs 92.85%, P < 0.05). But no significant differences were observed between the two groups in the incidences of moderate and severe OHSS, number of retrieved oocytes, and rates of fertilization, miscarriage and clinical pregnancy.</p><p><b>CONCLUSION</b>OCP for patients with PCOS can help to control the time of ovarian stimulation, improve the synchronism of follicular development, and increase the duration of gonadotropin stimulation and consumption, but cannot change the incidences of moderate and severe OHSS.</p>