Long versus short course treatment with metformin and clomiphene citrate for ovulation induction in women with PCOS

Background Polycystic ovary syndrome (PCOS) is the most common endocrinopathy among reproductive-aged women. Apart from infertility, women with PCOS often have other endocrine disorders, including insulin resistance, hyperinsulinaemia and hyperandrogenism. Metformin, combined with clomiphene citrate (CC), has been shown to be more effective in ovulation induction when compared with clomiphene citrate alone. The optimal duration for metformin pretreatment before initiation of clomiphene citrate, however, is unknown. Objectives To determine the effectiveness of short-course (less than four weeks) metformin plus CC versus long-course (four weeks or more) metformin plus CC with regard to ovulation and achievement of pregnancy in infertile women with PCOS. Search methods We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register, the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, EMBASE and PsycINFO (all from inception to 1 February 2012). Selection criteria Randomised controlled trials comparing short-course (less than four weeks) metformin plus CC versus long-course (four weeks or more) metformin plus CC for ovulation or achievement of pregnancy in infertile women with PCOS. Data collection and analysis No trials were found that met the selection criteria. Main results No randomised controlled trials were identified. Authors' conclusions There are insufficient data to determine whether short-course metformin pretreatment is as effective as the conventional long-course metformin pretreatment before initiation of clomiphene citrate for ovulation induction in infertile women with PCOS. A well-designed randomised controlled trial is needed to answer this important clinical question.