Effectiveness and safety of dydrogesterone in regularization of menstrual cycle: a post-marketing study.

Oral administration of dydrogesterone during second half of menstrual cycle has been shown to reduce menstrual irregularities. This prospective, observational study aimed to determine continued effectiveness of dydrogesterone (prescribed between 1 and 6 cycles or longer) in menstrual cycle regularization in Indian women aged ≥18 years with irregular menstrual cycle for at least 3 months. Those achieving regular cycles (21 to 35 days, inclusive) during treatment were followed up for 6 months after cessation of dydrogesterone treatment. Of the 910 women completing dydrogesterone treatment, 880 (96.7%) achieved cycle regularization (p<0.0001 for 90% success rate) at end of treatment (EOT). Of the 788 subjects available for follow up at 6 months, 747 (94.8%) reported cycle regularity (p<0.0001 for 90% success rate). At EOT, the mean cycle duration reduced by 16.14 (±24.04) days and mean amount of menstrual bleeding decreased by 0.45 (±1.20) pads/day. While five subjects reported worst pain at baseline, none experienced it at EOT. One serious adverse event (appendicitis) and three non-serious adverse events were reported. Dydrogesterone regularizes and improves the duration of the menstrual cycle, reduces the amount of bleeding, relieves menstrual pain and prevents relapse of irregular cycles at six months after discontinuation of treatment.