Effect of metformin on ovulation and reproductive outcomes in women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials

To evaluate the effect of MET on ovulation and reproductive outcomes in patients with polycystic ovary syndrome. Meta-analysis of available data from randomized controlled trials that examined the ovulation, pregnancy and live birth rate after the administration of clomiphene citrate (CC) or MET alone or combined. The ovulation rate was found to be higher in the group treated with MET combined with clomiphene citrate (CC) than only with CC, odds ratio (OR): 1.27, 95 % confidence interval (95 % CI) (1.03-1.56), while the pregnancy and live birth rate showed no significant difference between the two groups, OR: 1.19, 95 % CI (0.99-1.42) and OR: 0.99, 95 % CI (0.84-1.17), respectively. The MET + CC group produced a higher ovulation and pregnancy rate than MET group, OR: 2.10, 95 % CI (1.89-2.34) and OR: 2.08, 95 % CI (1.55-2.80), respectively, while between two groups the live birth rate showed no significant difference, OR: 1.50, 95 % CI (0.75-3.00). The ovulation rate was lower in MET than in CC group, OR: 0.65, 95 % CI (0.43-0.995), while between the two groups the pregnancy and live birth rate showed no significant difference, OR: 0.86, 95 % CI (0.42-1.74) and OR: 0.89, 95 % CI (0.71-1.13). The current study indicated that combination of MET and CC could gain advantage over a single administration in the ovulation induction and pregnancy rate.