Oligoovulatory and anovulatory cycles in women with polycystic ovary syndrome (PCOS): what's the difference?

Abstract

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder. The phenotype may differ between patients who exhibit signs of recent ovulation and anovulatory PCOS patients. Our objective was to study differences in clinical and endocrine characteristics and response to ovulation induction (OI) treatment comparing oligoovulatory and anovulatory PCOS patients. We conducted a retrospective cohort study at a tertiary hospital. PCOS patients (n=1750) presenting with oligo- or amenorrhea were diagnosed according to the Rotterdam 2003 consensus criteria. Arbitrarily, oligoovulatory PCOS was defined by a single random serum progesterone level of 10 nmol/liter or higher. We evaluated the incidence of oligo- or amenorrhea, menstrual cycle length, serum androgen levels, follicle count, and OI outcome parameters. Anovulatory women (n=1541 of 1750, 88.1%) were more often amenorrheic (P<0.001) and presented with a longer cycle duration (P<0.001) compared with oligoovulatory women (n=209 of 1750, 11.9%). Serum levels of testosterone (P<0.001), the free androgen index (P<0.001), and total follicle count (P<0.005) were higher in anovulatory compared with oligoovulatory patients. During clomiphene citrate OI, more oligoovulatory women gained regular menstrual cycles (P<0.05), whereas after second-line treatment with recombinant FSH, more anovulatory women became pregnant (P<0.05). Oligoovulatory women with PCOS exhibit a milder phenotype of ovarian dysfunction and have a more favorable response to OI treatment using clomiphene citrate compared with anovulatory PCOS patients. However, during second-line treatment with recombinant FSH, anovulatory PCOS patients presented with a higher chance of pregnancy compared with oligoovulatory patients.