BACKGROUNDHyperinsulinemia and insulin resistance are present in the majority of women with polycystic ovary syndrome (PCOS). Both metformin and rosiglitazone can improve the ovulation and endocrine disorders of the patients. How about the combination of the two? It is rarely reported. This study aimed to compare the therapeutic efficacy of metformin versus metformin plus rosiglitazone in patients with PCOS.

METHODSFifty-eight women with PCOS were randomly assigned to two groups. Metformin group (29) was treated with metformin mono-therapy and metformin plus rosiglitazone group (29) was treated with metformin plus rosiglitazone for 6 months. Treatment was discontinued once pregnancy was diagnosed.

RESULTSFasting insulin, postprandial insulin, the homeostatic model assessment of insulin resistance (HOMA-IR), luteinizing hormone (LH), triglyceride, lower density cholesterol and testosterone level decreased significantly in both groups (P < 0.05). Metformin plus rosiglitazone had a better effect than metformin mono-therapy. Body mass index decreased by 7.8% in metformin group while no significant change in metformin plus rosiglitazone group. There were eight pregnancies, six in metformin plus rosiglitazone group (one abortion) and two in metformin group. There was no congenital anomaly at birth and seven infants developed well at one year's follow-up.

CONCLUSIONSMetformin can improve insulin resistance and imbalance of endocrine hormones. Metformin plus rosiglitazone has a more pronounced therapeutic effect and achieved more pregnancies than mono-therapy with metformin. The use of metformin and rosiglitazone before pregnancy has no obvious side effect on the development of the infants. Our study might suggest that metformin is the better choice in PCOS patients with serious obese and rosiglitazone plus metformin would be more effective in patients with severe insulin resistance or those do not respond to metformin.