Metformin in polycystic ovary syndrome: systematic review and meta-analysis

Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process

Teede HJ et al., 2026 · Lancet (London, England) · Free to read

Polyendocrine metabolic ovarian syndrome (PMOS), previously named polycystic ovary syndrome (PCOS), affects one in eight women. However, the term PCOS is inaccurate, implying pathological ovarian cysts, obscuring diverse endocrine and metabolic features, and contributing to delayed diagnosis, fragmented care, and stigma, while curtailing research and policy framing. Building on an international mandate for change, we outline an unprecedented, rigorous, multistep global consensus process for the name change. Funding and governance were established with engagement of 56 leading academic, clinical, and patient organisations. Using iterative global surveys (with responses from 14 360 people with PCOS and multidisciplinary health professionals from all world regions), modified Delphi methods, nominal group technique workshops, and marketing and implementation analyses, we identified principles prioritising scientific accuracy, clarity, stigma avoidance, cultural appropriateness, and implementation feasibility. An accurate new name was prioritised over retaining the PCOS acronym or a generic name. Implementation approaches prioritised evolution rather than transformation. Preferred terms were polyendocrine, metabolic, and ovarian, reflecting the condition's multisystem pathophysiology, and polyendocrine metabolic ovarian syndrome was the consensus new name. Accuracy was improved by omitting cysts and by capturing endocrine, metabolic, and ovarian dysfunction. A co-designed global implementation strategy, including a transition period, education, and alignment with health systems and disease classification, is under way.

Evidence-based guideline: unexplained infertility

Romualdi D et al., 2023 · Hum Reprod · Free full text on PubMed Central

Guideline Group on Unexplained Infertility; Romualdi D(1), Ata B(2)(3), Bhattacharya S(4), Bosch E(5), Costello M(6)(7), Gersak K(8), Homburg R(9), Mincheva M(10), Norman RJ(7)(11), Piltonen T(12), Dos Santos-Ribeiro S(13), Scicluna D(14), Somers S(15), Sunkara SK(16), Verhoeve HR(17), Le Clef N(18).

Recommendations from the 2023 international evidence-based guideline for the assessment and management of PCOS

Teede HJ et al., 2023 · European Journal of Endocrinology · Free to read

Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome

Teede HJ et al., 2023 · Fertility and Sterility · Free to read

A systematic review of the reproductive system effects of metformin in patients with polycystic ovary syndrome

Costello MF et al., 2003 · Fertil Steril

To review the effectiveness of metformin in restoring regular menstrual cycles and ovulation and achieving pregnancy in women with polycystic ovary syndrome (PCOS). 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.

The Efficacy of 24-Month Metformin for Improving Menses, Hormones, and Metabolic Profiles in Polycystic Ovary Syndrome

Yang PK et al., 2018 · J Clin Endocrinol Metab

The long-term effects of metformin in women with polycystic ovarian syndrome (PCOS) are inadequately studied. The effects of metformin on women with PCOS during 24 months with respect to menses, hormones, and metabolic profiles are assessed. Prospective cohort. A reproductive endocrinology clinic in a university-affiliated medical center. One hundred nineteen women with PCOS, defined by the Rotterdam criteria, were enrolled. Metformin was given daily for 24 months. The primary outcome was the proportion of patients with regular menstruation during treatment. Changes in anthropometric, hormonal, and metabolic parameters were also assessed. Analyses were performed using segmented regression analysis with a generalized estimating equation methodology. Outcomes are expressed as magnitude of change from the baseline. Both overweight (OW) and normal-weight (NW) women with PCOS had increased menstrual frequency and decreased body mass index (BMI), testosterone, and luteinizing hormone levels in the first 6 months. Further stratification showed that NW women exhibiting elevated testosterone at baseline had the largest magnitude of improvement at 6 months [odds ratio (OR), 7.21; 95% confidence interval (CI), 2.35 to 22.17], whereas OW patients with normal testosterone were most likely to achieve normal menses at 12 months (OR, 0.63; 95% CI, 0.47 to 0.77). Metformin was associated with improvements in the menstrual cycle and most hormonal profiles in OW and NW women with PCOS during 24 months of treatment. Most parameters reached maximal response and steady-state after 6 months. Phenotypic differences in baseline BMI and testosterone level can be used as patient selection criteria or treatment prognostics.

Metformin therapy improves the menstrual pattern with minimal endocrine and metabolic effects in women with polycystic ovary syndrome

Morin-Papunen LC et al., 1998 · Fertil Steril

To determine the clinical, hormonal, and biochemical effects of 4-6 months of metformin therapy in obese patients with polycystic ovary syndrome (PCOS). Prospective study. The Gynecological Endocrine Unit of University Central Hospital, Oulu, Finland. PATIENT(S): Twenty obese patients with PCOS. INTERVENTION(S): Patients were treated with 0.5 g of metformin three times daily for 4-6 months. MAIN OUTCOME MEASURE(S): Clinical symptoms, menstrual pattern, and hirsutism, as well as serum concentrations of sex steroids, sex hormone-binding globulin (SHBG), gonadotropins, and lipids were assessed during the treatment. RESULT(S): Eleven women (68.8% of the women with menstrual disturbances) experienced more regular cycles during therapy. No changes in hirsutism, body mass index, or blood pressure occurred. The mean testosterone level was decreased significantly after 2 months of treatment but returned to the starting level by 4-6 months. Free testosterone levels decreased significantly during the treatment. There was no significant change in the levels of other sex steroids or lipids measured at 4-6 months of treatment. CONCLUSION(S): Metformin therapy is well tolerated by the majority of patients and may be clinically useful, especially in obese patients with PCOS and menstrual disturbances.

A brief update on the evidence supporting the treatment of infertility in polycystic ovary syndrome

Costello MF et al., 2019 · Aust N Z J Obstet Gynaecol

Polycystic ovary syndrome (PCOS) is complex with reproductive, metabolic and psychological features. Infertility is a prevalent presenting feature of PCOS with approximately 75% of these women suffering infertility due to anovulation, making PCOS by far the most common cause of anovulatory infertility. Previous guidelines either lacked rigorous evidence-based processes, did not engage consumer and international multidisciplinary perspectives, or were outdated. This review paper aims to provide a brief update on the best available and most current research evidence supporting the treatment of PCOS which informed the recommendations in the assessment and treatment of infertility section of the international evidence-based guideline on PCOS 2018. International evidence-based guideline development engaged professional societies and consumer organisations with multidisciplinary experts and women with PCOS directly involved at all stages. Lifestyle change alone is considered the first-line treatment for the management of infertile anovulatory PCOS women who are overweight or obese. Letrozole should now be considered first-line pharmacological treatment for ovulation induction to improve fertility outcomes. Clomiphene citrate alone and metformin alone could also be used as first-line pharmacological therapy, although both are less effective than letrozole and metformin is less effective than clomiphene citrate in obese women. Gonadotrophins or laparoscopic ovarian surgery are usually second-line ovulation induction therapies. In the absence of an absolute indication for in vitro fertilisation (IVF) / intracytoplasmic sperm injection, women with PCOS and anovulatory infertility could be offered IVF as third-line therapy where firstor second-line ovulation induction therapies have failed. This review provides the best available evidence informing recommendations (along with clinical expertise and consumer preference) which provide clinicians with clear advice on best practice for the management of infertile women with PCOS.