Influence of oral contraceptive pills on phenotype expression in women with polycystic ovary syndrome.

Polycystic ovarian syndrome (PCOS) is characterized by a heterogeneous phenotype including chronic anovulation, hyperandrogenism and polycystic ovaries. The use of oral contraceptive pills (OCP) alters features characteristic for the syndrome. In the present study, PCOS features were compared between women using or not using OCP at the time of the study. One hundred and one women diagnosed with normogonadotrophic anovulatory infertility were included. A total of 81 (80%) women were diagnosed with PCOS (revised 2003 criteria). From these women, a total of 54 did not use OCP, whereas 27 women did. Corrected for age, women taking OCP had increased serum concentrations of sex hormone-binding globulin (P < 0.001). Serum concentrations of testosterone (P = 0.04) and androstenedione (P = 0.01) were decreased. These differences resulted in a decreased free androgen index for women currently taking OCP compared with women without (P < 0.001). The mean ovarian volume/ovary and the mean follicle number/ovary were not different. Use of OCP influences phenotype expression (the observable trait) of individual women known to suffer from PCOS by reducing hyperandrogenism. Despite taking OCP, women still fulfilled the revised 2003 criteria for the syndrome, as PCO morphology was still present. Hence, OCP use does not appreciably affect the PCOS phenotype.