Metformin for Preventing Gestational Diabetes in Women with Polycystic Ovarian Syndrome

Objective: To assess the effect of metformin in controlling Gestational Diabetes Mellitus (GDM) in women with Polycystic Ovarian Syndrome (PCOS). Study Design: Comparative cohort study. Place and Duration of Study: Gynecology Clinics of Mamji Hospital, Karachi, from 2008 to 2010. Methodology: Patients who had been diagnosed Polycystic Ovarian Syndrome (PCOS) with hyperinsulinemia and conceived and continued pregnancy, were divided in two groups; 50 patients received metformin throughout pregnancy and 32 did not. Development of GDM was ascertained in both groups. The patients were followed throughout pregnancy and in puerperium with OGTT as per WHO criteria. Primary outcome measure was development of gestational diabetes mellitus. Comparison of continuous variables was done using student "t" test. For categorical variables, frequency and percentages are reported while, odds ratio is also estimated for GDM during pregnancy. Results: A total of 82 women with PCOS were included in this study, out of whom, 50 patients received metformin treatment while 32 patients did not. Pregnant women with PCOS in both groups were comparable in age, weight, parity and BMI. Mean fasting insulin levels at beginning of study entry were 17.22 +/- 2.3 mIU/L and 16.93 +/- 2.28 mIU/L in metformin and no metformin group respectively (p=0.589). Mean fasting blood sugar levels were 94.54 mg/dl in metformin and 99.59 mg/dl in no metformin group p < 0.001. A total of 5(10%) patients in metformin group developed GDM while 11 (34.37% OR 4.71, p = 0.01) developed GDM in no metformin group. Patients not receiving metformin were 4.7 times likely to have GDM (OR: 4.71) compared to those who received it. Conclusion: The frequency of gestational diabetes, was significantly higher in patients with PCOS who had not received metformin compared to those who did.