To review the effectiveness of metformin in restoring regular menstrual cycles and ovulation and achieving pregnancy in women with polycystic ovary syndrome (PCOS).
Design
Systematic review of pertinent studies identified using the bibliographic databases MEDLINE and EMBASE. References of selected articles identified were hand-searched for additional relevant citations.
PATIENT(S): Women with PCOS undergoing treatment with metformin alone, metformin combined with other methods of ovulation induction such as clomiphene citrate (CC) or gonadotropin injections, or metformin combined with in vitro fertilization (IVF).
RESULT(S): Thirty published studies were included in the overall review. Studies consisted of 12 randomized controlled trials, two cohort studies, and 16 uncontrolled descriptive studies. Due to a strong variability in the use of metformin according to study population, exposure, and outcome of interest, it was not possible to combine the data of the 12 randomized controlled trials to perform a meta-analysis. Limited data on predominately obese PCOS patients demonstrate that metformin alone improves both restoration of regular menses and spontaneous ovulation, but there are no data supporting an improvement in pregnancy rate. The addition of metformin to CC results in an improved ovulation and pregnancy rate in both unselected and CC-resistant PCOS women. There are insufficient data to make any conclusions on the effect of metformin on FSH ovulation induction or IVF.
CONCLUSION(S): The effectiveness and role of metformin in the treatment of PCOS anovulatory infertility in clinical practice is difficult to assess from currently available research. Further well-designed prospective, perhaps multicenter, randomized controlled trials with the primary end point of pregnancy or live-birth rate are required.
PMID 12524053 12524053 DOI 10.1016/s0015-0282(02)04554-5 10.1016/s0015-0282(02)04554-5 Costello et al. 2003, Costello 2003
Cite this article
Costello, M. F., & Eden, J. A. (2003). A systematic review of the reproductive system effects of metformin in patients with polycystic ovary syndrome. Fertility and sterility, 79(1), 1-13. https://doi.org/10.1016/s0015-0282(02)04554-5
Costello MF, Eden JA. A systematic review of the reproductive system effects of metformin in patients with polycystic ovary syndrome. Fertil Steril. 2003;79(1):1-13. doi:10.1016/s0015-0282(02)04554-5
Costello, Michael F., and John A. Eden. "A systematic review of the reproductive system effects of metformin in patients with polycystic ovary syndrome." Fertility and sterility, vol. 79, no. 1, 2003, pp. 1-13.
To assess the effectiveness of metformin in improving clinical and biochemical features of polycystic ovary syndrome. Systematic review and meta-analysis. Randomised controlled trials that investigated the effect of metformin compared with either placebo or no treatment, or compared with an ovulation induction agent. 13 trials were included for analysis, including 543 women with polycystic ovary syndrome that was defined by using biochemical or ultrasound evidence. Pregnancy and ovulation rates. Secondary outcomes of clinical and biochemical features of polycystic ovary syndrome. Meta-analysis showed that metformin is effective in achieving ovulation in women with polycystic ovary syndrome, with odds ratios of 3.88 (95% confidence interval 2.25 to 6.69) for metformin compared with placebo and 4.41 (2.37 to 8.22) for metformin and clomifene compared with clomifene alone. An analysis of pregnancy rates shows a significant treatment effect for metformin and clomifene (odds ratio 4.40, 1.96 to 9.85). Metformin has an effect in reducing fasting insulin concentrations, blood pressure, and low density lipoprotein cholesterol. We found no evidence of any effect on body mass index or waist:hip ratio. Metformin was associated with a higher incidence of nausea, vomiting, and other gastrointestinal disturbance. Metformin is an effective treatment for anovulation in women with polycystic ovary syndrome. Its choice as a first line agent seems justified, and there is some evidence of benefit on variables of the metabolic syndrome. No data are available regarding the safety of metformin in long term use in young women and only limited data on its safety in early pregnancy. It should be used as an adjuvant to general lifestyle improvements and not as a replacement for increased exercise and improved diet.
To evaluate the effects of metformin administration on spontaneous LH episodic release in a group of nonobese polycystic ovary (PCOS) patients. Controlled clinical study. PCOS patients in a clinical research environment. PATIENT(S): Twenty nonobese PCOS patients were enrolled after informed consent. INTERVENTION(S): All patients underwent hormonal evaluations and a pulsatility study (sampling every 10 minutes for 4 hours) before and at the sixth month of therapy (metformin, 500 mg, p.o. b.i.d.). Ultrasound examinations and Ferriman-Gallwey scoring were also performed. MAIN OUTCOME MEASURE(S): Measurements of plasma LH, FSH, estradiol (E(2)), androstenedione (A), 17-hydroxy-progesterone (17-OHP), and testosterone (T), glucose, insulin, and C-peptide concentrations. RESULT(S): After 6 months of metformin administration, the plasma LH, 17-OHP, A, and T levels and LH/FSH ratio were significantly reduced. Insulin sensitivity, expressed as the glucose-to-insulin ratio, was significantly improved under glucose load after 6 months of treatment. Spontaneous LH episodic release showed a significant reduction in pulse amplitude with no changes in pulse frequency. Menstrual cyclicity was restored in all amenorrheic and oligomenorrheic women. The ovarian volume and Ferriman-Gallwey scores also were significantly reduced. CONCLUSION(S): Metformin administration improves reproductive axis functioning in hyperandrogenic nonobese PCOS patients. By acting on the ovary and restoring normal ovarian activity, metformin positively modulates the reproductive axis (namely GnRH-LH episodic release).
In women suffering from polycystic ovary syndrome (PCOS), correction of hyperinsulinemia results enhances spontaneous ovulation or alternatively, the responsiveness to ovulation induction agents such as clomiphene citrate (CC). We investigated the effect of rosiglitazone maleate on ovulation induction in overweight and obese, CC-resistant women with PCOS. Double-blind, randomized, placebo-controlled trial. Academic reproductive endocrinology clinic. PATIENT(S): Overweight and obese women with clinical and laboratory manifestations of PCOS who desired pregnancy and were resistant to CC. INTERVENTION(S): Twenty-five women were randomized into two treatment groups. Subjects in Group I (n = 12) were randomized to receive rosiglitazone 4 mg b.i.d. with a placebo on cycle days 5-9. Group II (n = 13) was randomized to receive rosiglitazone 4 mg b.i.d. with CC on cycle days 5-9. The duration of the study was 2 months. MAIN OUTCOME MEASURE(S): The primary outcome was ovulation as defined by luteal serum progesterone greater than 5 ng/dL assessed on days 21, 24, and 28 of the cycle. Secondary outcomes were pregnancy and changes in insulin sensitivity, serum lipoproteins, and androgens. RESULT(S): Overall, 14 of 25 (56%) women, who were previously resistant to CC, successfully ovulated. In subjects taking rosiglitazone alone (Group I), 4 of 12 (33%) subjects ovulated compared with 10 of 13 (77%) women randomized to rosiglitazone with CC (Group II) (P=.04, Fisher's exact). One subject in Group I became pregnant, resulting in one uncomplicated live birth; two subjects in Group II conceived, with one successful live birth and one first trimester, spontaneous abortion. For all subjects, fasting insulin declined from 29.4 +/- 13.8 microU/mL to 17.3 +/- 7.8 microU/mL after rosiglitazone (P=.003, paired t-test). Although mean levels of total testosterone (T) and dehydroepiandrosterone sulfate (DHEAS) did not decline significantly, sex hormone-binding globulin (SHBG) did increase from 0.7 +/- 0.3 microg/dL to 1.0 +/- 0.3 microg/dL after rosiglitazone therapy (P=.001, paired t test). There was also a decrease in luteinizing hormone (LH) from 9.4 +/- 6.3 mU/mL to 7.2 +/- 3.7 mU/mL (P=.01). Lipoproteins including total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides did not change. Short-term rosiglitazone therapy enhances both spontaneous and clomiphene-induced ovulation in overweight and obese women with PCOS. Rosiglitazone therapy improves insulin sensitivity and decreases hyperandrogenemia primarily through increases in SHBG.
To investigate the effects of reduction of insulin resistance and hyperinsulinemia associated with the polycystic ovary syndrome (PCOS) on FSH-stimulated ovarian aromatase activity. Prospective study. Academic health center, Siena, Italy. PATIENT(S): Twenty women 18 to 26 years of age in whom PCOS was diagnosed on the basis of oligomenorrhea or amenorrhea and hyperandrogenemia. INTERVENTION(S): Recombinant FSH was administered. The next day, therapy with metformin (500 mg t.i.d.) was begun. After 35 to 40 days of treatment, the pretreatment protocol was repeated. MAIN OUTCOME MEASURE(S): Plasma levels of estradiol (E(2)), androstenedione (A), and testosterone (T). The ratios of basal levels and areas under the curve (AUCs) of products and substrates were compared before and after metformin administration to detect differences in aromatase activity. RESULT(S): Metformin treatment was associated with significant reduction in basal free testosterone plasma levels, insulin plasma levels, and insulin response to oral glucose tolerance testing. Administration of FSH was followed by a significantly lesser E(2) response after metformin therapy than before this therapy. The ratios of AUC(E2) to AUC(A) and to AUC(T), indicative of aromatase activity in response to FSH, were significantly lower after metformin therapy than before. CONCLUSION(S): Metformin therapy in women with PCOS is associated with a reduction in aromatase activity in response to FSH. Insulin affects production of both androgen and estrogen. Insulin therefore plays a central role in regulating the activity of thecal and granulosa cells.