A systematic review and meta-analysis of randomized controlled trials on metformin co-administration during gonadotrophin ovulation induction or IVF in women with polycystic ovary syndrome

Interventions to prevent or reduce the incidence and severity of ovarian hyperstimulation syndrome: a systematic umbrella review of the best clinical evidence

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threating iatrogenic complication of the early luteal phase and/or early pregnancy after in vitro fertilization (IVF) treatment. The aim of the current study was to identify the most effective methods for preventing of and reducing the incidence and severity of OHSS in IVF patients. A systematic review of systematic reviews of randomized controlled trials (RCTs) with meta-analysis was used to assess each potential intervention (PROSPERO website, CRD 268626) and only studies with the highest quality were included in the qualitative analysis. Primary outcomes included prevention and reduction of OHSS incidence and severity. Secondary outcomes were maternal death, incidence of hospital admission, days of hospitalization, and reproductive outcomes, such as incidence of live-births, clinical pregnancies, pregnancy rate, ongoing pregnancy, miscarriages, and oocytes retrieved. A total of specific interventions related to OHSS were analyzed in 28 systematic reviews of RCTs with meta-analyses. The quality assessment of the included studies was high, moderate, and low for 23, 2, and 3 studies, respectively. The certainty of evidence (CoE) for interventions was reported for 37 specific situations/populations and resulted high, moderate, and low-to-very low for one, 5, and 26 cases, respectively, while it was not reported in 5 cases. Considering the effective interventions without deleterious reproductive effects, GnRH-ant co-treatment (36 RCTs; OR 0.61, 95% C 0.51 to 0.72, n = 7,944; I² = 31%) and GnRH agonist triggering (8 RCTs; OR 0.15, 95% CI 0.05 to 0.47, n = 989; I² = 42%) emerged as the most effective interventions for preventing OHSS with a moderate CoE, even though elective embryo cryopreservation exhibited a low CoE. Furthermore, the use of mild ovarian stimulation (9 RCTs; RR 0.26, CI 0.14 to 0.49, n = 1,925; I² = 0%), and dopaminergic agonists (10 RCTs; OR 0.32, 95% CI 0.23 to 0.44, n = 1,202; I² = 13%) coadministration proved effective and safe with a moderate CoE. In conclusion, the current study demonstrates that only a few interventions currently can be considered effective to reduce the incidence of OHSS and its severity with high/moderate CoE despite the numerous published studies on the topic. Further well-designed RCTs are needed, particularly for GnRH-a down-regulated IVF cycles.

Metformin: new applications for an old drug

Metformin is a biguanide, evolved as one of the most widely used medicines. The applications of this component include but are not limited to reducing blood glucose, weight loss, and polycystic ovary syndrome. Studies about other probable indications have emerged, indicating that this agent can also be utilized for other purposes. In this review, applications of metformin are noticed based on the current evidence. Metformin commonly is used as an off-label drug in non-alcoholic fatty liver disease (NAFLD), but it worsens inflammation and should not be used for this purpose, according to the latest research. Metformin decreased the risk of death in patients with liver cirrhosis. It is an effective agent in the prevention and improvement of survival in patients suffering hepatocellular carcinoma. There is evidence of the beneficial effects of metformin in colorectal cancer, early-stage prostate cancer, breast cancer, urothelial cancer, blood cancer, melanoma, and bone cancer, suggesting metformin as a potent anti-tumor agent. Metformin shows neuroprotective effects and provides a potential therapeutic benefit for mild cognitive impairment and Alzheimer's disease (AD). It also has been shown to improve mental function and reduce the incidence of dementia. Another condition that metformin has been shown to slow the progression of is Duchenne muscular dystrophy. Regarding infectious diseases, tuberculosis (TB) and coronavirus disease (COVID-19) are among the conditions suggested to be affected by metformin. The beneficial effects of metformin in cardiovascular diseases were also reported in the literature. Concerning renal function, studies showed that daily oral administration of metformin could ameliorate kidney fibrosis and normalize kidney structure and function. This study reviewed the clinical and preclinical evidence about the possible benefits of metformin based on recent studies. Numerous questions like whether these probable indications of metformin can be observed in non-diabetics, need to be described by future basic experiments and clinical studies.

Effects of metformin treatment on pregnancy outcomes in patients with polycystic ovary syndrome

INTRODUCTION

This review covers the current evidence regarding the use of metformin as a therapeutic intervention for optimizing pregnancy outcomes in women with polycystic ovary syndrome (PCOS).

AREAS COVERED

After searching Medline, Embase and CINAHL, all important large clinical trials and observational studies plus systematic reviews, meta-analyses and Cochrane reviews have been summarized here. The results have been compared to culminate in a thorough review and discussion on the use of metformin in relation to reproductive outcomes for women with PCOS. The role of metformin in PCOS is explored both in terms of achieving conception and during pregnancy. The existing evidence around metformin use is summarized both during the preconceptual period and during pregnancy, in relation to reproductive outcomes.

EXPERT OPINION

Metformin is a widely used medication, often prescribed to improve reproductive outcomes for women with PCOS. However, the evidence remains equivocal regarding its efficacy both in optimizing fertility and pregnancy outcomes. More research is required with special emphasis on metformin use within different populations, including ethnic groups and women with varying BMI ranges.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.

Rescue In Vitro Maturation in Polycystic Ovarian Syndrome Patients Undergoing In Vitro Fertilization Treatment who Overrespond or Underrespond to Ovarian Stimulation: Is It A Viable Option? A Case Series Study

Background

This study intends to present the role of rescue in vitro maturation (IVM) in polycystic ovarian syn- drome (PCOS) patients undergoing in vitro fertilization (IVF) treatment who have inappropriate responses to ovarian stimulation.

Materials and Methods

This was a retrospective case series study of five PCOS patients undergoing IVF treatment considered for cycle cancellation due to increased risk of ovarian hyperstimulation syndrome (OHSS) as group A or poor response to ovarian stimulation as group B. Patients in group A had high oestradiol levels and recruitment of high numbers of small/intermediate sized follicles that did not meet the criteria for human chorionic gonadotropin (hCG) triggering. Patients in group B responded inadequately to hormonal stimulation despite high gonadotropin dosage. Treatment was changed to rescue IVM cycles after the patients provided consent.

Results

In group A, three IVF patients deemed to have high chances of developing OHSS as evidenced by high oestradiol levels were converted to IVM. A total of the 58/68 oocytes retrieved were mature or matured in vitro. There were 26 cleaving embryos obtained. Two patients had live births and one patient suffered a miscarriage. In group B, rescue IVM was implemented in two patients due to poor ovarian response (POR). A total of 22/26 oocytes retrieved were mature or matured in vitro. There were 13 cleaving embryos obtained. One patient had a live birth, whilst the other suffered a miscarriage.

Conclusion

Rescue IVM could be a viable option in PCOS patients undergoing IVF treatment who are unable to safely meet the criteria for hCG triggering due to overresponse to ovarian stimulation or ovarian resistance to high doses of stimulation. Conversion to IVM can still result in reasonable oocyte retrieval and lead to clinical pregnancy and live births without the risks of OHSS.

Evidence summaries and recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome: assessment and treatment of infertility

STUDY QUESTION

What is the recommended assessment and management of infertile women with polycystic ovary syndrome (PCOS), based on the best available evidence, clinical expertize and consumer preference?

SUMMARY ANSWER

International evidence-based guidelines, including 44 recommendations and practice points, addressed prioritized questions to promote consistent, evidence-based care and improve the experience and health outcomes of infertile women with PCOS.

WHAT IS KNOWN ALREADY

Previous guidelines on PCOS lacked rigorous evidence-based processes, failed to engage consumer and multidisciplinary perspectives or were outdated. The assessment and management of infertile women with PCOS are inconsistent. The needs of women with PCOS are not being adequately met and evidence practice gaps persist.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Governance included a six continent international advisory and a project board, a multidisciplinary international guideline development group (GDG), consumer and translation committees. Extensive health professional and consumer engagement informed the guideline scope and priorities. The engaged international society-nominated panel included endocrinology, gynaecology, reproductive endocrinology, obstetrics, public health and other experts, alongside consumers, project management, evidence synthesis and translation experts. Thirty-seven societies and organizations covering 71 countries engaged in the process. Extensive online communication and two face-to-face meetings over 15 months addressed 19 prioritized clinical questions involving nine evidence-based reviews and 10 narrative reviews. Evidence-based recommendations (EBRs) were formulated prior to consensus voting within the guideline panel.

STUDY DESIGN, SIZE, DURATION

International evidence-based guideline development engaged professional societies and consumer organizations with multidisciplinary experts and women with PCOS directly involved at all stages. A (AGREE) II-compliant processes were followed, with extensive evidence synthesis. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was applied across evidence quality, desirable and undesirable consequences, feasibility, acceptability, cost, implementation and ultimately recommendation strength. The guideline was peer-reviewed by special interest groups across our partner and collaborating societies and consumer organizations, was independently assessed against AGREE II criteria and underwent methodological review. This guideline was approved by all members of the GDG and has been approved by the NHMRC.

MAIN RESULTS AND THE ROLE OF CHANCE

The quality of evidence (QOE) for the EBRs in the assessment and management of infertility in PCOS included very low (n = 1), low (n = 9) and moderate (n = 4) quality with no EBRs based on high-quality evidence. The guideline provides 14 EBRs, 10 clinical consensus recommendations (CCRs) and 20 clinical practice points on the assessment and management of infertility in PCOS. Key changes in this guideline include emphasizing evidence-based fertility therapy, including cheaper and safer fertility management.

LIMITATIONS, REASONS FOR CAUTION

Overall evidence is generally of low to moderate quality, requiring significantly greater research in this neglected, yet common condition. Regional health systems vary and a process for adaptation of this guideline is provided.

WIDER IMPLICATIONS OF THE FINDINGS

The international guideline for the assessment and management of infertility in PCOS provides clinicians with clear advice on best practice based on the best available evidence, expert multidisciplinary input and consumer preferences. Research recommendations have been generated and a comprehensive multifaceted dissemination and translation program supports the guideline with an integrated evaluation program.

STUDY FUNDING/COMPETING INTEREST(S)

The guideline was primarily funded by the Australian National Health and Medical Research Council of Australia (NHMRC) supported by a partnership with ESHRE and the American Society for Reproductive Medicine (ASRM). GDG members did not receive payment. Travel expenses were covered by the sponsoring organizations. Disclosures of conflicts of interest were declared at the outset and updated throughout the guideline process, aligned with NHMRC guideline processes. Dr Costello has declared shares in Virtus Health and past sponsorship from Merck Serono for conference presentations. Prof. Norman has declared a minor shareholder interest in the IVF unit Fertility SA, travel support from Merck and grants from Ferring. Prof. Norman also has scientific advisory board duties for Ferring. The remaining authors have no conflicts of interest to declare.

This article was not externally peer-reviewed by Human Reproduction Open.

[Which ovarian stimulation to which women: The polycystic ovary syndrome (PCOS)]

Polycystic ovarian syndrome (PCOS) is a frequent pathology in the young woman, linking infertility to a metabolic disease. Initial support will include a plan (in the case of overweight or obesity) to lose at least 5 to 10% of the weight. Subsequently, clomiphene citrate is the first treatment for ovulation induction with pregnancy rates of 40 to 80% after 6 cycles. If there is resistance to clomiphene citrate, the choice will be between the ovarian drilling (50-60% of pregnancy in the year following, including the half spontaneous) or ovarian stimulation with gonadotropins. The risk of ovarian stimulation in these women is hyperstimulation and multiple pregnancies. We also discuss the place of the GnRH pulsatile administration, insulin-sensitizers, in vitro fertilization and in vitro maturation in these women. Once infertility support, these women should be long-term followed because of the neoplasic and cardiovascular risks they present.

Insulin Sensitizers Modulate GnRH Receptor Expression in PCOS Rats

BACKGROUND

Insulin sensitizers like metformin and pioglitazone are clinically used since last decades for the treatment of PCOS, but their efficacy and possible role in PCOS patients remains questionable. Also, the mechanism by which these insulin sensitizers show effect is not clear.

AIM OF THE STUDY

To evaluate the effect of metformin and pioglitazone on leutinizing hormone and follicle stimulating hormone receptor mRNA expression, hyperandrogenism and insulin resistance in high fat diet induced and letrozole induced PCOS in rats.

METHODS

Pre-pubertal female rats were divided into four groups: group I received normal pellet diet and group II, III and IV received high fat diet. After 105 d of dietary manipulation, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Similarly, adult female rats were divided into four groups: group I received 1% carboxymethyl cellulose (CMC) and group II, III, IV received letrozole for 21 d. After 21 d of letrozole administration, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Oral glucose tolerance test, lipid profile, fasting glucose, insulin, estrus cycle, hormonal profile, ovary weight, leutinizing hormone receptor and follicle stimulating hormone receptor mRNA expression was measured. Polycystic ovarian morphology was assessed through histopathological changes of ovary.

RESULTS AND CONCLUSION

Metformin and pioglitazone treatment improve both metabolic and reproductive parameters of PCOS including hyperinsulinemia and hyperandrogenism. LH receptor and FSH receptor mRNA expression were altered by pioglitazone and metformin treatment.

Contemporary approaches to the management of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common disorder in women in their reproductive years and is characterized by androgen excess, ovulatory dysfunction, and polycystic ovarian morphology. It is also associated with several metabolic abnormalities, particularly insulin resistance and obesity, which play an important role in the pathophysiology of PCOS and, in particular, negatively influence ovarian function and fertility. This review article summarizes the available treatment for women with PCOS. Specifically, current and potentially new therapies are discussed.

Impact of Metformin on IVF Outcomes in Overweight and Obese Women With Polycystic Ovary Syndrome: A Randomized Double-Blind Controlled Trial

OBJECTIVES

To evaluate the impact of metformin on in vitro fertilization (IVF) outcomes in overweight and obese women with polycystic ovary syndrome (PCOS).

METHODS

This was a randomized double-blind placebo-controlled study ( ClinicalTrials.gov : NCT02910817) carried out in a University IVF Center. The study included 102 overweight and obese women (body mass index [BMI] >24 kg/m²) with PCOS who underwent their first fresh autologous IVF-embryo transfer cycle and agreed to participate in the study. The study participants were randomized into 2 groups: metformin group received metformin (1000 mg per day) at the start of controlled ovarian stimulation (COH) until the day of the pregnancy check, and placebo group received placebo tablets in the same duration. The primary outcome measure was the total number of retrieved oocytes.

RESULTS

Both groups were homogenous in baseline demographic characteristics. Metformin group versus the placebo group demonstrated decrease in the mean number of the retrieved oocytes (9.06 ± 4.23 vs 16.86 ± 8.3, P < .01) and similar live birth rate (LBR; 25.5% vs 17.6%, P = .34). The number of fertilized oocytes was lower in the metformin group (5.65 ± 2.66 vs 9 ± 4.55, P < .01). However, the fertilization rate was similar in both groups (62.3% vs 53.4%, P = .10). There was no difference in the implantation rate (15.7% vs 11.8%, P = .32), multiple pregnancy rate (13.4% vs 3.9%, P = .08), or miscarriage rate (23.5% vs 35.7%, P = .46). No cases of ovarian hyperstimulation syndrome (OHSS) were observed in both groups.

CONCLUSION

Short-term administration of metformin to overweight or obese women with PCOS undergoing IVF decreased number of the retrieved oocytes but did not improve the LBR.

SYNOPSIS

Metformin use could decrease the number of retrieved oocytes in overweight and obese women with polycystic ovary syndrome undergoing IVF.

The effect of metformin use on pregnancy rates among polycystic ovary syndrome patients undergoing in vitro fertilization: A retrospective-cohort study

Background

Metformin is widely used with gonadotropins by women with polycystic ovary syndrome (PCOS) during in vitro fertilization (IVF) to increase their chances of pregnancy. The aim of this study was to evaluate the efficacy of metformin in improving the rates of clinical pregnancy among women with PCOS undergoing IVF.

Methods

This was a retrospective cohort study of women with PCOS, aged 18–40 years, undergoing IVF during 2006–2012 at a University Hospital in Riyadh, Saudi Arabia. Baseline patient data including menstrual frequency, biochemical parameters such as fasting serum insulin (FSI) concentration, comorbidities, and the rates of ovulation and pregnancy were collected. Pregnancy rates were compared between the metformin and non-metformin groups.

Results

A total of 210 women with PCOS met the inclusion criteria and were included in the study. Of the 210 women with PCOS, 109 of them received metformin in addition to gonadotropins. Patients who received metformin were 16% less likely to be pregnant in comparison with those who did not receive metformin (OR = 0.840; 95% CI = 0.710–0.993; P = 0.0415), when controlled for baseline prolactin level, testosterone level, lipid panel, FSI concentration, fasting plasma glucose (FPG) concentration, comorbidities, duration of infertility, daily metformin dosage, and the previous use of clomiphene and/or leuprolide.

Conclusions

Metformin co-treatment during IVF may negatively affect pregnancy rates. Further well-designed, randomized, double-blind placebo-control clinical trials are needed to confirm the findings of this study.

Effect of metformin and oral contraceptives on polycystic ovary syndrome and IVF cycles

AIM

The aim of this study is to investigate the effect of metformin and/or OC added to the treatment of PCOS patients at our clinic on IVF outcome.

MATERIALS AND METHODS

This study is a retrospective study that assesses the data of PCOS patients who received IVF between 2005 and 2015 at a private IVF center. The study included 496 PCOS cases aged between 24 and 40. Participants diagnosed with PCOS were divided into 4 groups according to the use of metformin and OC prior to the IVF cycle: 11.1% were in the metformin group, 31.3% in the OC group, 14.9% in the Metformin + OC group, and 42.7% in the control group.

RESULTS

No difference was found in the total gonadotropin dose and duration of stimulation between the groups. Clinical pregnancy rates and implantation rates were similar in all groups, although the numbers of oocytes, mature oocytes, fertilized oocytes, and transferred embryos were lower in the treatment groups received metformin compared to the OC group and control group. There was no significant difference in the presence of OHSS and the singleton and multiple pregnancies between the four groups.

CONCLUSION

The present study established no positive role of metformin and OC use in increasing the treatment success in IVF/ICSI cycles in PCOS patients. It would be appropriate to limit the use of these agents with special indications such as decreasing insulin resistance or synchronizing follicular cohort.

Strategies for improving outcome of assisted reproduction in women with polycystic ovary syndrome: systematic review and meta-analysis

OBJECTIVES

To identify, appraise and summarize the current evidence regarding the efficacy of strategies aimed at improving assisted reproductive techniques in women with polycystic ovary syndrome (PCOS).

METHODS

A comprehensive literature search of the standard medical databases was performed. The last electronic search was run in July 2015. The primary outcome measures were live birth/ongoing pregnancy and ovarian hyperstimulation syndrome (OHSS). The secondary outcome measures were clinical pregnancy and miscarriage.

RESULTS

We screened 1021 records and completely assessed 173, finally including 66 studies in the quantitative analysis. Many different interventions were assessed, however the overall quality of the studies was low. We observed moderate-quality evidence that there is no clinically relevant difference in live birth/ongoing pregnancy rates (relative risk (RR), 0.95 (95% CI, 0.84-1.08)), or clinical pregnancy (RR, 1.02 (95% CI, 0.91-1.15)) when comparing antagonist and agonist protocols for ovarian stimulation. Additionally, we found low-quality evidence that metformin improves live birth/ongoing pregnancy (RR, 1.28 (95% CI, 1.01-1.63)) and clinical pregnancy rates (RR, 1.26 (95% CI, 1.04-1.53)) when compared with placebo or no intervention. We further found low-quality evidence that there is no clinically relevant difference in live birth/ongoing pregnancy rates (RR, 1.03 (95% CI, 0.80-1.34)) and clinical pregnancy rates (RR, 0.99 (95% CI, 0.81-1.22)) when comparing human menopausal gonadotropin for inducing ovulation and artificial preparation with estradiol valerate for endometrial preparation for frozen embryo transfer (FET). Low-quality evidence suggests that mannitol compared with no intervention (RR, 0.54 (95% CI, 0.39-0.77)) and antagonist protocols compared with agonist protocols (RR, 0.63 (95% CI, 0.49-0.80)) reduce rates of OHSS.

CONCLUSION

There is low- to moderate-quality evidence suggesting that antagonist protocols are preferable to agonist ones, because they reduce the incidence of OHSS without interfering with clinical pregnancy and live birth for women with PCOS. Additionally there is low-quality evidence pointing to a benefit of metformin supplementation on clinical pregnancy and live birth; and that ovulation induction and administration of estradiol seem to be equally effective for endometrial preparation before FET for women with PCOS. For all other interventions, the evidence is of very low quality, not allowing any meaningful conclusions to be drawn. Estrategias para mejorar el resultado de la reproducción asistida en mujeres con síndrome de ovario poliquístico: revisión sistemática y metaanálisis RESUMEN OBJETIVOS: Identificar, evaluar y resumir la evidencia actual sobre la eficacia de las estrategias para mejorar las técnicas de reproducción asistida en mujeres con síndrome de ovario poliquístico (SOP). MÉTODOS: Se realizó una búsqueda exhaustiva de literatura en las bases de datos médicas estándar. La última búsqueda electrónica se realizó en julio de 2015. Las medidas de resultado primarias fueron los nacimientos vivos/embarazos en curso y el síndrome de hiperestimulación ovárica (SHO). Las medidas de resultado secundarias fueron el embarazo confirmado ecográficamente y el aborto.

RESULTADOS

Se cribaron 1021 registros, de los que se evaluaron por completo 173, para finalmente incluir 66 estudios en el análisis cuantitativo. Aunque se evaluaron muchas intervenciones diferentes, en general la calidad de los estudios fue baja. Se observó evidencia de calidad moderada de que no hay diferencias relevantes clínicamente en las tasas de nacimientos vivos/embarazos en curso (riesgo relativo (RR): 0,95 (IC 95%, 0,84-1,08)), o de embarazos confirmados ecográficamente (RR: 1,02 (IC 95%, 0,91-1,15)), cuando se comparan los protocolos de antagonistas y agonistas para la estimulación ovárica. Además, se encontró evidencia de baja calidad en que la metformina mejora las tasas de nacimientos vivos/embarazos en curso (RR: 1,28 (IC 95%, 1,01-1,63)) y de embarazos confirmados ecográficamente (RR: 1,26 (IC 95%, 1,04-1,53)) en comparación con un placebo o la no intervención. Se encontró también evidencia de baja calidad en que no hay diferencias relevantes clínicamente en las tasas de nacimientos vivos/embarazos en curso (RR: 1,03 (IC 95%, 0,80-1,34)) y las tasas de embarazos confirmados ecográficamente (RR: 0,99 (IC 95%, 0.81-1,22)) al comparar la gonadotropina menopáusica humana para la inducción de la ovulación y la preparación artificial con el valerato de estradiol para preparar el endometrio para la transferencia de embriones congelados (TEC). La baja calidad de la evidencia sugiere que el manitol, en comparación con la no intervención (RR: 0,54 (IC 95%, 0,39-0,77)), y los protocolos de antagonistas, en comparación con los protocolos de agonistas (RR: 0,63 (IC 95%, 0,49-0,80)), reducen las tasas de SHO. CONCLUSIÓN: Hay evidencia de calidad baja a moderada que sugiere que los protocolos de antagonistas son preferibles a los de agonistas, ya que reducen la tasa de SHO sin interferir con el embarazo confirmado ecográficamente y los nacimientos vivos en las mujeres con SOP. Además, existe evidencia de baja calidad que indica un beneficio del uso de metformina como aporte suplementario en embarazos confirmados ecográficamente y en nacimientos vivos; y que la inducción de la ovulación y la administración de estradiol parecen ser igualmente eficaces para la preparación del endometrio antes de la TEC en mujeres con SOP. Para el resto de procedimientos, la evidencia es de muy baja calidad, y por ello no permite extraer conclusiones importantes.

A short course of metformin does not reduce OHSS in a GnRH antagonist cycle for women with PCOS undergoing IVF: a randomised placebo-controlled trial

STUDY QUESTION

Does 'metformin' reduce the incidence of ovarian hyperstimulation syndrome (OHSS) for women with polycystic ovary syndrome (PCOS) undergoing a GnRH antagonist assisted conception treatment cycle?

SUMMARY ANSWER

A short course of metformin does not reduce the incidence of OHSS for women with PCOS undergoing a GnRH antagonist treatment cycle.

WHAT IS KNOWN ALREADY

Metformin does reduce the incidence of OHSS in a GnRH-agonist treatment cycle.

STUDY DESIGN, SIZE, DURATION

A randomised placebo-controlled trial (RCT) using metformin or placebo. Randomisation was blinded to both patient and investigator, using a random permuted blocks method with a 50:50 allocation ratio. The study was completed over 5 years (2009-2014) with 153 randomised patients. A sample size calculation based on the incidence of OHSS was completed prospectively suggesting a minimum of 146 recruits was required for the trial with a power of 80% and a type 1 error of 0.05.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients met the Rotterdam criteria for PCOS and were treated with a standard GnRH antagonist IVF/ICSI treatment cycle in a tertiary infertility clinic. The study medication was started prior to stimulation and continued to oocyte retrieval. Of the 153 patients, 77 received metformin and 76 placebo.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no reduction in the incidence of moderate-severe OHSS (Placebo (PLA) 12.2%, metformin (MET) = 16%, 95% CI -0.08-0.16, P = 0.66). There was no difference in total gonadotrophin dose (PLA = 1200, MET = 1200, 95% CI -118.67-118.67, P = 0.75), oocytes retrieved (PLA = 15, MET = 14, 95% CI -2.37-4.37, P = 0.66) or fertilisation rate (PLA = 60.7%, MET = 53.3%, 95% CI -0.96-14.94, P = 0.07). However, using metformin resulted in a reduced clinical pregnancy rate (CPR) per cycle started (PLA = 48.7%, MET = 28.6%, 95% CI 0.04-0.35, P = 0.02) and live birth rate (PLA = 51.6%, MET = 27.6%, 95% CI 0.05-0.40, P = 0.02). Furthermore, when ethnicity was taken into account there was a significant reduction in pregnancy outcome for the South Asian population irrespective of metformin or placebo use (CPR per cycle started, White Caucasian = 44.4%, South Asian = 19.4%; 95% CI 0.06-0.39, P = 0.01).

LIMITATIONS, REASONS FOR CAUTION

This study was only undertaken on an infertility population with PCOS with a limited duration of study medication use.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first adequately powered RCT to assess the impact of metformin on OHSS in a high-risk group (women with PCOS) undergoing a GnRH antagonist cycle. It does not support the empirical prescribing of metformin as an adjunct to a GnRH antagonist treatment cycle.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

EudraCT number 2009-010952-81.

TRIAL REGISTRATION DATE

21 September 2009.

DATE OF FIRST PATIENT'S ENROLMENT

30 October 2009.

Twenty years of ovulation induction with metformin for PCOS; what is the best available evidence?

The potential reproductive benefits of metformin, a drug endowed with the capacity to ameliorate insulin resistance in polycystic ovary syndrome (PCOS), has garnered much interest over the past 2 decades. In this review, randomized-controlled trials (RCT) and meta-analyses of RCT comparing metformin are critically appraised and summarized. PubMed and CENTRAL databases were consulted. Evidence is insufficient to favour the use of metformin or metformin plus clomiphene citrate instead of clomiphene citrate for ovulation induction in women with newly diagnosed PCOS. Evidence is also insufficient to recommend metformin as a primary treatment for non-obese women with PCOS. Metformin plus clomiphene citrate should be considered as an effective option in clomiphene citrate-resistant PCOS. In women with PCOS undergoing gonadotrophin ovulation induction, metformin significantly increased pregnancy and live birth rates (P < 0.0001 and P = 0.020, respectively) with reduced risk of cancelled cycles. A beneficial effect of metformin co-treatment in increasing clinical pregnancy rates and reducing the risk of OHSS in PCOS patients undergoing assisted reproduction techniques has been shown. No evidence was found of reduced risk of spontaneous abortion or increased risk of major anomalies in women with PCOS taking metformin during the first trimester.

Polycystic ovary syndrome: chemical pharmacotherapy

INTRODUCTION

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disease among women of childbearing age. The clinical features are heterogeneous and vary in intensity. Hirsutism, menstrual disorders and infertility are the most frequent conditions observed; however, long-term complications (dyslipidemia, hypertension, cardiovascular disease, type 2 diabetes mellitus, endometrial cancer) are also often described. Each disorder may be managed by tailored strategies, employing sequential or combined pharmacological and/or non-pharmacological treatment.

AREAS COVERED

The authors review the drugs used for PCOS management and discuss new approaches. A systematic MEDLINE search regarding the randomized controlled trials, retrospective and observational studies about medical treatments of PCOS, the Cochrane library for reviews and also search for registered trials on ClinicalTrials.gov is performed.

EXPERT OPINION

A uniform treatment for PCOS patients does not exist. Clinicians should perform an accurate evaluation of patients' characteristics, identifying the phenotypic target and, subsequently, the best-tailored treatment to manage one or more clinical issues. Lifestyle intervention should always be the first recommended approach unless other issues indicate that drug or hormonal interventions are superior.

Prevention of Ovarian Hyperstimulation Syndrome: A Review

The following review aims to examine the available evidence to guide best practice in preventing ovarian hyperstimulation syndrome (OHSS). As it stands, there is no single method to completely prevent OHSS. There seems to be a benefit, however, in categorizing women based on their risk of OHSS and individualizing treatments to curtail their chances of developing the syndrome. At present, both Anti-Müllerian Hormone and the antral follicle count seem to be promising in this regard. Both available and upcoming therapies are also reviewed to give a broad perspective to clinicians with regard to management options. At present, we recommend the use of a "step-up" regimen for ovulation induction, adjunct metformin utilization, utilizing a GnRH agonist as an ovulation trigger, and cabergoline usage. A summary of recommendations is also made available for ease of clinical application. In addition, areas for potential research are also identified where relevant.

The prevention of ovarian hyperstimulation syndrome

OBJECTIVE

To review the clinical aspects of ovarian hyperstimulation syndrome and provide recommendations on its prevention.

OPTIONS

Preventative measures, early recognition, and prompt systematic supportive care will help avoid poor outcomes.

OUTCOMES

Establish guidelines to assist in the prevention of ovarian hyperstimulation syndrome, early recognition of the condition when it occurs, and provision of appropriate supportive measures in the correct setting.

EVIDENCE

Published literature was retrieved through searches of Medline, Embase, and the Cochrane Library from 2011 to 2013 using appropriate controlled vocabulary ([OHSS] ovarian hyperstimulation syndrome and: agonist IVF, antagonist IVF, metformin, HCG, gonadotropin, coasting, freeze all, agonist trigger, progesterone) and key words (ovarian hyperstimulation syndrome, ovarian stimulation, gonadotropin, human chorionic gonadotropin, prevention). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English. There were no date restrictions. Searches were updated on a regular basis and incorporated in the guideline to February 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Summary Statements 1. The particular follicle-stimulating hormone formulation used for ovarian stimulation does not affect the incidence of ovarian hyperstimulation syndrome. (I) 2. Coasting may reduce the incidence of severe ovarian hyperstimulation syndrome. (III) 3. Coasting for longer than 3 days reduces in vitro fertilization pregnancy rates. (II-2) 4. The use of either luteinizing hormone or human chorionic gonadotropin for final oocyte maturation does not influence the incidence of ovarian hyperstimulation syndrome. (I) 5. There is no clear published evidence that lowering the human chorionic gonadotropin dose will result in a decrease in the rate of ovarian hyperstimulation syndrome. (III) 6. Cabergoline starting from the day of human chorionic gonadotropin reduces the incidence of ovarian hyperstimulation syndrome in patients at higher risk and does not appear to lower in vitro fertilization pregnancy rates. (II-2) 7. Avoiding pregnancy by freezing all embryos will prevent severe prolonged ovarian hyperstimulation syndrome in patients at high risk. (II-2) 8. Pregnancy rates are not affected when using gonadotropin-releasing hormone (GnRH) agonists in GnRH antagonist protocols for final egg maturation when embryos are frozen by vitrification for later transfer. (II-2) Recommendations 1. The addition of metformin should be considered in patients with polycystic ovarian syndrome who are undergoing in vitro fertilization because it may reduce the incidence of ovarian hyperstimulation syndrome. (I-A) 2. Gonadotropin dosing should be carefully individualized, taking into account the patient's age, body mass, antral follicle count, and previous response to gonadotropins. (II-3B) 3. Cycle cancellation before administration of human chorionic gonadatropin is an effective strategy for the prevention of ovarian hyperstimulation syndrome, but the emotional and financial burden it imposes on patients should be considered before the cycle is cancelled. (III-C) 4. Gonadotropin-releasing hormone (GnRH) antagonist stimulation protocols are recommended in patients at high risk for ovarian hyperstimulation syndrome (OHSS). The risk of severe OHSS in patients on GnRH antagonist protocols who have a very robust ovarian stimulation response can be reduced by using a GnRH agonist as a substitute for human chorionic gonadotropin to trigger final oocyte maturation. (I-B) 5. A gonadotropin-releasing hormone (GnRH) antagonist protocol with a GnRH agonist trigger for final oocyte maturation is recommended for donor oocyte and fertility preservation cycles. (III-C) 6. Albumin or other plasma expanders at the time of egg retrieval are not recommended for the prevention of ovarian hyperstimulation syndrome. (I-E) 7. Elective single embryo transfer is recommended in patients at high risk for ovarian hyperstimulation syndrome. (III-C) 8. Progesterone, rather than human chorionic gonadotropin, should be used for luteal phase support. (I-A) 9. Outpatient culdocentesis should be considered for the prevention of disease progression in severe ovarian hyperstimulation syndrome. (II-2B).

Everolimus, an mTOR pathway inhibitor, is highly successful on ovarian hyperstimulation syndrome by reducing ovarian weight and progesterone levels: a preclinical experimental randomized controlled study

The usefulness of various pathways inhibitors, Everolimus, an inhibitor of mammalian target of rapamycin (mTOR), Infliximab, a monoclonal antibody which blocks the tumor necrosis factor-a (TNF-a), Erlotinib, a tyrosine protein kinase inhibitor of the epidermal growth factor receptor (EGFR), Metformin, an activator of AMP-activated protein kinase enzyme (AMPK) and vascular permeability reducers were explored in an ovarian hyperstimulation syndrome (OHSS) rat model. Sixty-three female Wistar rats were randomly divided in seven groups. The control group received saline, while the OHSS group received recombinant -- follicle-stimulating hormone (rec-FSH) for four consecutive days. The other five groups received rec-FSH for 4 d and Everolimus daily, Infliximab once, Erlotinib daily, Metformin daily and Vitamin C daily, respectively. All groups received human chorionic gonadotropin (hCG) at the fifth day. The efficacy of Everolimus administration for various intervals was also explored. Significantly reduced ovarian weight was observed in the Everolimus group (rec-FSH + hCG + mTOR inhibitor) compared to the OHSS group (p < 0.001). The Everolimus group also showed the lowest progesterone (PRG) concentration (p = 0.007). The Erlotinib group (rec-FSH + hCG + EGFR inhibitor) presented with the lowest graafian follicle number, while the Everolimus group was characterized by the lowest corpus luteum number. The vascular permeability and the estradiol levels did not differ between groups. Finally, the Everolimus intra-comparison showed no difference in all measured outcomes. Studying the different pathways linked to vascular endothelial growth factor (VEGF) pathway, we conclude that targeting mTOR pathways is beneficial for reducing ovarian weight and PRG levels in an OHSS animal model.

Metformin treatment before and during IVF or ICSI in women with polycystic ovary syndrome

BACKGROUND

The use of insulin-sensitising agents, such as metformin, in women with polycystic ovary syndrome (PCOS) who are undergoing ovulation induction or in vitro fertilisation (IVF) cycles has been widely studied. Metformin reduces hyperinsulinaemia and suppresses the excessive ovarian production of androgens. As a consequence, it is suggested that metformin could improve assisted reproductive techniques (ART) outcomes, such as ovarian hyperstimulation syndrome (OHSS), pregnancy and live birth rates.

OBJECTIVES

To determine the effectiveness and safety of metformin as a co-treatment during IVF or intracytoplasmic sperm injection (ICSI) in achieving pregnancy or live birth in women with PCOS.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, LILACS, the metaRegister of Controlled Trials and reference lists of articles (up to 15 October 2014).

SELECTION CRITERIA

Types of studies: randomised controlled trials (RCTs) comparing metformin treatment with placebo or no treatment in women with PCOS who underwent IVF or ICSI treatment.

TYPES OF PARTICIPANTS

women of reproductive age with anovulation due to PCOS with or without co-existing infertility factors.Types of interventions: metformin administered before and during IVF or ICSI treatment.Types of outcome measures: live birth rate, clinical pregnancy rate, miscarriage rate, incidence of ovarian hyperstimulation syndrome , incidence of participant-reported side effects, serum oestradiol level on the day of trigger, serum androgen level, and fasting insulin and glucose levels.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies, extracted the data according to the protocol and assessed study quality. The overall quality of the evidence was assessed using GRADE methods.

MAIN RESULTS

We included nine randomised controlled trials involving a total of 816 women with PCOS. When metformin was compared with placebo there was no clear evidence of a difference between the groups in live birth rates (OR 1.39, 95% CI 0.81 to 2.40, five RCTs, 551 women, I(2) = 52%, low-quality evidence). Our findings suggest that for a woman with a 32 % chance of achieving a live birth using placebo or other treatment, the corresponding chance using metformin treatment would be between 28% and 53%.When metformin was compared with placebo or no treatment, clinical pregnancy rates were higher in the metformin group (OR 1.52; 95% CI 1.07 to 2.15; eight RCTs, 775 women, I(2) = 18%, moderate-quality evidence). This suggests that for a woman with a 31% chance of achieving a clinical pregnancy using placebo or no treatment, the corresponding chance using metformin treatment would be between 32% and 49%.The risk of ovarian hyperstimulation syndrome was lower in the metformin group (OR 0.29; 95% CI 0.18 to 0.49, eight RCTs, 798 women, I(2) = 11%, moderate-quality evidence). This suggests that for a woman with a 27% risk of having OHSS without metformin the corresponding chance using metformin treatment would be between 6% and 15%.Side effects (mostly gastrointestinal) were more common in the metformin group (OR 4.49, 95% CI 1.88 to 10.72, for RCTs, 431 women, I(2)=57%, low quality evidence)The overall quality of the evidence was moderate for the outcomes of clinical pregnancy, OHSS and miscarriage, and low for other outcomes. The main limitations in the evidence were imprecision and inconsistency.

AUTHORS' CONCLUSIONS

This review found no conclusive evidence that metformin treatment before or during ART cycles improved live birth rates in women with PCOS. However, the use of this insulin-sensitising agent increased clinical pregnancy rates and decreased the risk of OHSS.

Are growth factor receptors modulated by metformin in human endometrial stromal cells after stimulation with androgen and insulin?

OBJECTIVE

To assess the effect of metformin on gene and protein expression of insulin receptor (IR) and IGF-1 (IGF-1R) receptor in human endometrial stromal cells after stimulation with androgen and insulin.

STUDY DESIGN

Primary culture of endometrial stromal cells stimulated with estrogen, progesterone with or without androgen or insulin, and treated with metformin for 24 and 48 h, followed by RNA (qRT-PCR) and protein (Western blot) extraction and analysis.

RESULTS

IR gene expression was increased after treatment with insulin (2.9-fold change, p = 0.027) and further after metformin treatment (4.7-fold change, p < 0.001), and in IGF-1R, the group treated with insulin (1.83-fold change) and metformin (1.78-fold change) showed more expression, than control group (p < 0.001). Similarly, IR protein expression was increased after addition of metformin and insulin (249,869 ± 15,878) in relation to the other groups (p < 0.001). Furthermore, cells treated with insulin (153,634 ± 29,123) and androgen plus insulin (162,854 ± 86,258) had a higher IR protein expression compared to control (104,654 ± 5,634) and androgen group (71,595 ± 3,439, (p = 0.045 and 0.021). In groups treated with insulin (127,711 ± 4,591) and androgen plus insulin (151,098 ± 5,194) the protein IGF-1R was increased compared to control (79,355 ± 3,470) and the androgen-only group (79,326 ± 3,114) (p < 0.001).

CONCLUSION

Metformin in combination with insulin increased IR protein and gene expressions, while it had no influence on the protein expression of IGF-1R in endometrial stromal cells.

Metformin and gonadotropins for ovulation induction in patients with polycystic ovary syndrome: a systematic review with meta-analysis of randomized controlled trials

The current systematic review with meta-analysis of randomized controlled trials (RCTs) was aimed to evaluate the effects of metformin on reproductive outcomes in patients with polycystic ovary syndrome (PCOS) who receive gonadotropins for ovulation induction. After systematic review of electronic databases and websites for registration of RCTs, a total of 7 RCTs reporting data on 1023 cycles were included in the final analysis. Descriptive data showed an overall low studies' quality due to unclear sequence generation and allocation concealment, lack of blinding procedure, incomplete outcome data and several biases and/or confounders. Data synthesis showed that metformin improved live-birth (odds ratio [OR] = 1.94, 95% confidence interval [CI] 1.10 to 3.44; P = 0.020) and pregnancy (OR = 2.25, 95% CI 1.50 to 3.38; P < 0.0001) rates, without significant heterogeneity across the studies (P = 0.230, estimation of inconsistency = 30%; and P = 0.710, estimation of inconsistency = 0%, respectively, for live-birth and pregnancy rates). A significant reduction of cancellation rate was observed after metformin administration (OR = 0.41, 95% CI 0.24 to 0.72, P = 0.002) without significant heterogeneity across the studies (P = 0.500, estimation of inconsistency = 0%). Metformin administration influenced or did not influence other secondary endpoints assessed with a significant heterogeneity. In conclusion, metformin administration increases the live-birth and pregnancy rate in PCOS patients who receive gonadotropins for ovulation induction. Further well designed, blinded, placebo-controlled, and adequately powered RCTs are need to confirm that metanalytic results.

Genetic variants associated with insulin signaling and glucose homeostasis in the pathogenesis of insulin resistance in polycystic ovary syndrome: a systematic review

BACKGROUND

Polycystic ovary syndrome must be recognized as a serious issue due to its implication on long term health regardless of an individual's age. PCOS and insulin resistance are interlinked, as approximately 40 % of women with PCOS are insulin resistant. However, the detailed molecular basis for insulin resistance that is coupled with PCOS remains poorly understood.

OBJECTIVE

To review the published evidence that polymorphisms in genes that are involved in insulin secretion and action are associated with an increased risk of PCOS.

METHODS

We reviewed articles published through November 2012 which concerned polymorphisms of genes related to insulin signaling and glucose homeostasis as well as their associations with PCOS. The articles were identified via Medline searches.

CONCLUSIONS

No consistent evidence emerged of a strong association between the risk of PCOS and any known gene that is related to insulin signaling and glucose homeostasis. Moreover, recent genome-wide association studies are inconsistent in identifying the associations between PCOS and insulin metabolism genes. Many of the studies reviewed were limited by heterogeneity in the PCOS diagnosis and by not have having a sufficient number of study participants. Further studies are warranted to determine predisposing risk factors which could modify environmental factors and thus reduce the risk of PCOS. Large genome-wide association studies devoted solely to PCOS will be necessary to identify new candidate genes and proteins that are involved in PCOS risk.

Body weight reduction and metformin: Roles in polycystic ovary syndrome

BACKGROUND AND OBJECTIVES

Polycystic ovary syndrome (PCOS) is a common problem in women at fertile age. A prospective study was conducted to clarify the pathophysiological responses during an application of insulin sensitizer, metformin and weight reduction therapy at the Gynecology Center in Ohud hospital, in AL-Madinah AL-Munawarah, Kingdom of Saudi Arabia.

METHODOLOGY

Twenty healthy women served as controls and 180 PCOS women divided into three groups participated in the study. First group was treated with Clomid citrate 100mg/day from the 2nd day of menses to the 6th day plus gonadotrophin from day three to the 13th. Group II was treated as group I plus 850mg metformin twice a day and group III was treated as group I plus weight reduction. Clinical symptoms, menstrual pattern, hirsutism, blood glucose, body mass index, waist-to-hip ratio, insulin, hormonal, and lipid profiles were assessed pre- and post treatment. Insulin resistance was calculated.

RESULTS

PCOS women had significantly higher values than the healthy women in most of the measurements. Metformin and weight reduction therapy resulted in a significant decrease in the fasting insulin, glucose/insulin ratio and HOMA-IR. Metformin and weight reduction therapy resulted in a significant decrease in the lipid parameters, testosterone, LH/FSH ratio, SHBG, and prolactin levels. HOMA-IR was significantly higher in women with PCOS. HOMA-IR was positively correlated with testosterone, estradiol, TG, total cholesterol and LDL-cholesterol parameters, and negatively correlated with HDL-cholesterol and FSH levels.

CONCLUSION

Metformin therapy and weight reduction had favorable influences on the basic metabolic and hormonal profiles in women with PCOS and that metformin and lifestyle modification (weight reduction via diet restriction or exercise) resulted in a significantly greater weight loss than hormonal therapy alone. Metformin and weight reduction therapy decreased also hyperandrogenism and insulin resistance.

The treatment of infertility in polycystic ovary syndrome: a brief update

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. Lifestyle change alone is considered the first-line treatment for the management of infertile anovulatory PCOS women who are overweight or obese. First-line medical ovulation induction therapy to improve fertility outcomes is clomiphene citrate, whilst gonadotrophins, laparoscopic ovarian surgery or possibly metformin are second line in clomiphene citrate-resistant PCOS women. There is currently insufficient evidence to recommend aromatase inhibitors over that of clomiphene citrate in infertile anovulatory PCOS women in general or specifically in therapy naive or clomiphene citrate-resistant PCOS women. IVF/ICSI treatment is recommended either as a third-line treatment or in the presence of other infertility factors.

Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation (anovulation), high levels of male hormones (hyperandrogenaemia) and high levels of insulin (hyperinsulinaemia secondary to increased insulin resistance). Hyperinsulinaemia is associated with an increase in cardiovascular risk and the development of diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating the features of PCOS, including anovulation.

OBJECTIVES

To assess the effectiveness of insulin-sensitising drugs in improving reproductive outcomes and metabolic parameters for women with PCOS.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 3rd Quarter 2011), CINAHL (October 2011), MEDLINE (January 1966 to October 2011), and EMBASE (January 1985 to October 2011).

SELECTION CRITERIA

Randomised controlled trials of insulin sensitising drugs compared with either placebo, no treatment, or an ovulation induction agent for women with PCOS, menstrual disturbance and subfertility.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and trial quality, and extracted data.  

MAIN RESULTS

Forty-four trials (3992 women) were included for analysis, 38 of them using metformin and involving 3495 women.There was no evidence that metformin improved live birth rates, whether it was used alone (pooled OR 1.80, 95% CI 0.52 to 6.16, 3 trials, 115 women) or in combination with clomiphene (pooled OR 1.16, 95% CI 0.85 to 1.56, 7 trials, 907 women). However, clinical pregnancy rates were improved for metformin versus placebo (pooled OR 2.31, 95% CI 1.52 to 3.51, 8 trials, 707 women) and for metformin and clomiphene versus clomiphene alone (pooled OR 1.51, 95% CI 1.17 to 1.96, 11 trials, 1208 women). In the studies that compared metformin and clomiphene alone, there was evidence of an improved live birth rate (pooled OR 0.3, 95% CI 0.17 to 0.52, 2 trials, 500 women) and clinical pregnancy rate (pooled OR 0.34, 95% 0.21 to 0.55, 2 trials, 500 women) in the group of obese women who took clomiphene.Metformin was also associated with a significantly higher incidence of gastrointestinal disturbances than placebo (pooled OR 4.27, 95% CI 2.4 to 7.59, 5 trials, 318 women) but no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

In agreement with the previous review, metformin was associated with improved clinical pregnancy but there was no evidence that metformin improves live birth rates whether it is used alone or in combination with clomiphene, or when compared with clomiphene. Therefore, the role of metformin in improving reproductive outcomes in women with PCOS appears to be limited.

Evidence-Based Lifestyle and Pharmacological Management of Infertility in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine disorder in women of reproductive age and by far the most common cause of anovulatory infertility. Lifestyle change alone, and not in combination with pharmacological ovulation induction such as clomifene citrate or metformin, is generally considered the first-line treatment for the management of infertile anovulatory women with PCOS who are overweight or obese. Clomifene citrate should be considered as a first-line pharmacological therapy to improve fertility outcomes. Second-line medical treatments may include ovulation induction with gonadotropins (in clomifene citrate-resistant or clomifene citrate failure women) or laparoscopic ovarian drilling (in clomifene citrate-resistant women) or possibly with metformin combined with clomifene citrate (in clomifene citrate-resistant women). There is currently insufficient evidence to recommend aromatase inhibitors over that of clomifene citrate in infertile anovulatory women with PCOS in general or specifically in therapy-naive or clomifene citrate-resistant women with PCOS.

Predicting and preventing ovarian hyperstimulation syndrome (OHSS): the need for individualized not standardized treatment

Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of controlled ovarian stimulation (COS) as part of assisted reproductive technologies (ART). While the safety and efficacy of ART is well established, physicians should always be aware of the risk of OHSS in patients undergoing COS, as it can be fatal. This article will briefly present the pathophysiology of OHSS, including the key role of vascular endothelial growth factor (VEGF), to provide the foundation for an overview of current techniques for the prevention of OHSS. Risk factors and predictive factors for OHSS will be presented, as recognizing these risk factors and individualizing the COS protocol appropriately is the key to the primary prevention of OHSS, as the benefits and risks of each COS strategy vary among individuals. Individualized COS (iCOS) could effectively eradicate OHSS, and the identification of hormonal, functional and genetic markers of ovarian response will facilitate iCOS. However, if iCOS is not properly applied, various preventive measures can be instituted once COS has begun, including cancelling the cycle, coasting, individualizing the human chorionic gonadotropin trigger dose or using a gonadotropin-releasing hormone (GnRH) agonist (for those using a GnRH antagonist protocol), the use of intravenous fluids at the time of oocyte retrieval, and cryopreserving/vitrifying all embryos for subsequent transfer in an unstimulated cycle. Some of these techniques have been widely adopted, despite the scarcity of data from randomized clinical trials to support their use.

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

The study aim was to evaluate our personal experience regarding the use and the reproductive effect of metformin administration in a large population of infertile patients with polycystic ovary syndrome (PCOS) undergoing gonadotropins ovarian stimulation for in vitro fertilization (IVF). Infertile patients with PCOS undergoing gonadotropins ovarian stimulation with (metformin group, n = 191) or without (control group, n = 187) metformin and IVF were evaluated. Treatment characteristics, patients' data and reproductive outcomes were evaluated. In all cases, metformin with an immediate-release formulation was administered, and in most of cases it was given as pre- and co-treatment (74.9%) and at a dosage of 1700 mg/day (59.7%). Stimulation length and gonadotropins doses were significantly (p < 0.05) higher in metformin group than in control group. The number of dominant follicles on day of ovarian maturation triggering and peak oestradiol levels were significantly (p < 0.05) lower in metformin group than in control group. Cycle cancellation rate under metformin resulted significantly influenced by interaction with body mass index (BMI), age and basal follicle-stimulating hormone (FSH) levels. Notwithstanding, metformin use in infertile PCOS patients who receive gonadotropins for IVF is not standardized, it seems to modulate the ovarian response to stimulation. This effect may benefit or harm on the basis of ovarian reserve and patients' characteristics.

Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of assisted reproduction technology. The syndrome is characterized by cystic enlargement of the ovaries and a fluid shift from the intravascular to the third space due to increased capillary permeability and ovarian neoangiogenesis. Its occurrence is dependent on the administration of human chorionic gonadotrophin (hCG). β-hCG and its analogs, estrogen, estradiol, prolactin, histamine and prostaglandins have all been implicated in OHSS but now it is increasingly better understood that the vasoactivesubstances such as interleukins, tumor necrosis factor-α, endothelin-1, and vascular endothelial growth factor (VEGF) secreted by the ovaries have been implicated in increasing vascular permeability. Enlargement of the ovaries causes abdominal pain, nausea and vomiting. Leakage of fluid from follicles, increased capillary permeability leading to third spacing (due to the release of vasoactive substances), or frank rupture of follicles can all cause ascites. Due to leakage of fluid through the impaired blood vessels both within and outside the ovary there is massive fluid-shift from the intra-vescular bed to the third compartment results in intravascular hypovolemia with concomitant development of edema, ascites, hydrothorax and/or hydropericardium. Low-dose gonadotrophin protocols have been implemented to reduce the risks of fertility treatment in polycystic ovary syndrome patients. Prophylactic albumin administration may interrupt the development of OHSS by increasing the plasma oncotic pressure and binding mediators of ovarian origin. OHSS is significantly lower in an antagonist protocol than in an agonist protocol. Cabergoline inhibits partially the VEGF receptor 2 phosphorylation levels and associated vascular permeability without affecting luteal angiogenesis reduces the 'early' (within the first 9 days after hCG) onset of OHSS. To prevent thrombosis, subcutaneous heparin 5000-7500 U/d is begun on the first day of admission. These patients need a hospital ward where the clinical picture is well understood and the personnel have expertise in its treatment and follow-up. Admission to an intensive care unit is necessary when critical OHSS develops.

Does metformin affect the ovarian response to gonadotropins for in vitro fertilization treatment in patients with polycystic ovary syndrome and reduced ovarian reserve? A randomized controlled trial

OBJECTIVE

To evaluate the effects of metformin on the ovarian response to gonadotropins given for in vitro fertilization (IVF) programs in patients with polycystic ovary syndrome (PCOS) and reduced ovarian reserve.

DESIGN

Prospective, parallel, randomized, double-blind, placebo-controlled clinical trial.

SETTING

Academic departments of obstetrics and gynecology, and a private IVF center.

PATIENT(S)

Primary infertile patients with PCOS older than 35 years and/or with a basal follicle-stimulating hormone (FSH) level higher than 10 IU/L who were scheduled for IVF cycles.

INTERVENTION(S)

Gonadotropin-releasing hormone agonist flare-up protocol and high starting doses of recombinant FSH plus metformin or placebo tablets.

MAIN OUTCOME MEASURE(S)

Primary end point: cancellation rate for low ovarian response. Secondary end-points: other clinical, biochemical, and reproductive data.

RESULT(S)

Enrollment was stopped after 88 participants had been randomized and analyzed due to an unacceptable increased risk of poor ovarian response in the metformin arm. Statistically significant differences between the metformin and placebo groups were observed in the dose of gonadotropins used, peak estradiol levels, and the number of dominant follicles, retrieved oocytes, and metaphase II oocytes.

CONCLUSION(S)

In patients with PCOS and reduced ovarian reserve, metformin worsened the response to gonadotropins, and its administration should be stopped before the start of controlled ovarian hyperstimulation for IVF programs. CLINICAL TRIALS IDENTIFICATION NUMBER: NCT01208740.

[Ovarian hyperstimulation syndrome: pathophysiology, risk factors, prevention, diagnosis and treatment]

The ovarian hyperstimulation syndrome is a major complication of ovulation induction for in vitro fertilization, with severe morbidity and possible mortality. Whereas its pathophysiology remains ill-established, the VEGF may play a key role as well as coagulation disturbances. Risk factors for severe OHSS may be related to patients characteristics or to the management of the ovarian stimulation. Two types of OHSS are usually distinguished: the early OHSS, immediately following the ovulation triggering and a later and more severe one, occurring in case of pregnancy. As no etiologic treatment is available, the therapeutic management of OHSS should focus on its related-complications. Thrombotic complications that can occur in venous or arterial vessels represent the major risk of OHSS, possibly conducting to myocardial infarction and cerebrovascular accidents. Once the OHSS is diagnosed, prevention of thrombotic accidents remains the major issue.