RESUMEN
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 PCOS women. SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (December 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, 2006 issue 4), MEDLINE (1950 to 7 January 2007), CINAHL (1982 to December 2006) and EMBASE (1980 to 7 January 2007). 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 PCOS women. 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-chouse metformin pretreatment is as effective as the conventional long-course metformin pretreatment before initiation of clomiphene citrate for ovulation induction in infertile PCOS patients. A well-designed randomised controlled trial is needed to answer this important clinical question.