Metformin administration in patients with polycystic ovary syndrome who receive gonadotropins for in vitro fertilization cycles: 10-year experience in a large infertile population

A systematic review and meta-analysis of metformin among patients with polycystic ovary syndrome undergoing assisted reproductive technology procedures

BACKGROUND

Metformin is used among patients with polycystic ovary syndrome (PCOS), but findings for its effects on outcomes of assisted reproductive technology (ART) have been conflicting.

OBJECTIVES

To compare ART outcomes among women with PCOS who were and were not given metformin.

SEARCH STRATEGY

Databases were searched for reports published in English between 2002 and 2013, using combinations of the terms "polycystic ovary syndrome," "PCOS," "insulin-sensitizing," and "metformin."

SELECTION CRITERIA

Randomized controlled trials of metformin versus placebo among women with PCOS undergoing ART were included if they assessed rates of pregnancy, live birth, spontaneous abortion, multiple pregnancy, and/or ovarian hyperstimulation syndrome (OHSS).

DATA COLLECTION AND ANALYSIS

Data were extracted from included studies. The Mantel-Haenzel random-effects model was used for meta-analyses.

MAIN RESULTS

Twelve studies (1516 participants) were included. No significant differences were recorded between metformin and placebo groups for rates of pregnancy (risk ratio [RR] 1.11, 95% CI 0.92-1.33), live birth (RR 1.12, 0.92-1.36), spontaneous abortion (RR 1.00, 0.60-1.67), or multiple pregnancy (RR 0.96, 0.47-1.96). However, OHSS rate was significantly lower among patients who received metformin than among those who received placebo (RR 0.44, 0.26-0.77).

CONCLUSIONS

Metformin does not improve ART outcomes among patients with PCOS, but does significantly reduce their risk of OHSS.

Evaluation of endocrine changes in women with the polycystic ovary syndrome during metformin treatment

The aim of study was to evaluate endocrine changes in PCOS women during metformin treatment. One hundred women with PCOS, aged 20-40 years were included. A complete hormonal and metabolic pattern was recorded for each subject every 6 months. Metformin treatment after 6 and 12 months significantly reduced weight, BMI, waist circumference, insulin and HOMA-IR (p=0.000) with high differences of variances within repeated measurements. There was significant reduction of PRL, testosterone and estradiol (p=0.000) with small differences within repeated measurements. Metformin did not have effect on TSH. However, results showed important reduction of CRP, LH, LH/FSH, androstendione, DHEA-S and progesterone (p=0.000) with moderate differences within measures. Metformin restored menstrual cyclicity in most participants. At baseline in study group was 69% women with oligomenorrhoea, amenorrhoea or polymenorrhoea. After 12 months of treatment, only 20% PCOS women had irregular menstrual cycle (p=0.000). Hirsutism was also reduced. Intriguingly, during first 6 months of treatment in PCOS women 9 pregnancies occurred (p=0.000), while during last 6 months treatment were 2 pregnancies (p=0.317), in total 11(13%). Multiple regression model revealed that the presence of anovulation in PCOS women was strongly associated with BMI, waist, FSH and age. Insulin resistance was significantly predicted by BMI, cholesterol, progesterone and presence of hirsutism. The metformin therapy significantly improved insulin resistance, imbalance of endocrine hormones, hirsutism and menstrual cyclicity in women with PCOS. The most important predictors for duration of metformin treatment in PCOS women were testosterone, progesterone, FSH, CRP and presence of anovulation.