The preferred treatment for irregular menstrual cycle is medical management with progesterone¹. Progestins have a major role in the prevention of recurrent episodes of menstrual irregularities. It stops endometrial growth and support and organize estrogen-primed endometrium. When progestin therapy is discontinued, an organized slough to the basalis layer of the endometrium occurs, which allows for a rapid cessation of bleeding. In the treatment of oligomenorrhoea, orderly limited withdrawal bleeding can be accomplished by administration of a progestin in a cyclic manner. In the treatment of dysfunctional menorrhagia and polymenorrhoea, progestins are prescribed for up to 2 weeks (to induce stabilizing pre-decidual stromal changes followed by a withdrawal flow). Thereafter, repeat progestin therapy is offered cyclically to ensure therapeutic effect ².Duphaston, containing dydrogesterone as an active ingredient, is an orally active retro-progesterone which differs only slightly in molecular structure from natural progesterone^{3, 4}. Dydrogesterone has been widely used worldwide for various gynaecological and obstetric indications. It produces a complete secretory endometrium in an oestrogen-primed uterus thereby providing protection for estrogen induced increased risk for endometrium hyperplasia and/or carcinogenesis. It is indicated in all cases of endogenous progesterone deficiency and has no estrogenic, no androgenic, no thermogenic, no anabolic and no corticoid activity⁵.

After oral administration of labelled dydrogesterone on average 63% of the dose is excreted into the urine and within 72 hours excretion is complete. Dydrogesterone is completely metabolized and the main metabolite is 20α-dihydrodydrogesterone (DHD) and is present in the urine predominantly as   the glucuronic acid conjugate. A common feature of all metabolites characterized is the retention of the 4, 6diene-3-one configuration of the parent compound and the absence of 17 α-hydroxylation and explains the lack of estrogenic and androgenic effects of dydrogesterone. After oral administration of dydrogesterone, plasma concentrations of DHD are substantially higher as compared to the parent drug. Dydrogesterone is rapidly absorbed. Its mean terminal half lives of dydrogesterone and DHD vary between 5 to 7 and 14 to 17 hours, respectively. Dydrogesterone is not excreted in urine as pregnanediol, like progesterone. Analysis of endogenous progesterone production based on pregnanediol excretion therefore remains possible⁵.

The current study is designed as a non-interventional, observational study.  Patients diagnosed with irregular menstrual cycles will be prescribed Duphaston as per the physician’s clinical practice in accordance of the local marketing authorization with regards to dose, population and indication. The patients will be included in the study subject to their consent.