The effects of metformin on insulin resistance, clomiphene-induced ovulation and pregnancy rates in women with polycystic ovary syndrome

Effectiveness of inositol, metformin and their combination in women with PCOS undergoing assisted reproduction: systematic review and meta-analysis

OBJECTIVE

Our study aims to compare the effect of metformin, inositol and their combinations on the efficiency in improving outcomes of assisted reproductive technologies in women with PCOS.

DATA SOURCES

PubMed, The Cochrane Library, ClinicalTrials.gov, Embase, MEDLINE. The search was performed on studies published before November 14, 2021, to identify articles evaluating the effectiveness of treatment metformin and inositol on ART outcomes.

STUDY SELECTION

The systematic review was conducted according to the PRISMA 2020 checklist and registered in the PROSPERO 2021 CRD42021287887. Randomized controlled trials (RCTs) in English that compared metformin or inositol or metformin + inositol treatment with placebo or no treatment in women with PCOS undergoing assisted reproduction were included. In addition, RCTs with comparison combination and single metformin or inositol treatment were also included.

DATA EXTRACTION AND SYNTHESIS

35 RCTs were included for qualitative analysis reporting on 4668 participants. In group of Metformin treatment were included 1891 patients, in Myo-inositol group - 281, in inositol + metformin group were included 110 participants and in control group (placebo or absence of treatment) - 1865 women with PCOS. 5 meta-analyses were performed. CPR in comparison of metformin and placebo in 1312 patients were higher in metformin group (RR = 1.30, 95% CI: 1.12 to 1.50, p = 0.0004). OHSS was less in metformin (RR = 0.34, 95% CI: 0.17 to 0.69, p = 0.003). However, LBR were not statistically significant (RR = 1.12, 95% CI: 0.93 to 1.36, p = 0.24). In comparison of inositol and no treatment there was also no difference in CPR (RR = 1.37, 95% CI: 0.79 to 2.38, p = 0.26). As for metformin and inositol meta-analysis in 220 patients with PCOS, CPR were higher in inositol group (RR = 1.52, 95% CI: 1.05 to 2.18, p = 0.03). Combination treatment included only two RCTs and was illegible for meta-analysis.

CONCLUSION

To our knowledge, it is the first meta-analysis that estimates inositol treatment compared to metformin. Based on our systematic review and meta-analysis, metformin seems to be a good option for improving ART outcomes in women with PCOS. However, it is not clear whether inositol usage is adequate. Nevertheless, we need more clinical trials of good quality to answer all questions thoroughly.

Therapeutic efficacy of clomiphene citrate combined with metformin in patients with polycystic ovary syndrome

WHAT IS KNOWN AND OBJECTIVE

Although several clinical trials have compared the clinical efficacy of clomiphene citrate (CC) combined with metformin (MET) in the treatment of women with polycystic ovary syndrome (PCOS), the results are controversial. Therefore, this study was designed to conduct a pooled analysis to evaluate the efficacy of CC combined with MET versus CC in these patients.

METHODS

Computerized searches of the PubMed, Web of Science, Embase and Cochrane Library databases were conducted to identify eligible randomized controlled trials (RCTs) from the data obtained up to June 2021. The Cochrane Collaboration risk of bias tool was used to assess the risk of bias in individual RCTs, and RevMan 5.4 was used for data statistical analysis.

RESULTS AND DISCUSSION

A total of 13 RCTs were included in the meta-analysis. These studies involved 1,353 patients, 707 of these were in the combination group and 646 in the monotherapy group. The results indicated a higher clinical pregnancy rate (risk ratio [RR] 1.28, 95% confidence interval [CI] 1.06-1.54, p = 0.01) in the combined group compared to the monotherapy group. However, no significant differences were observed in the ovulation rate (RR 1.13, 95% CI 0.98-1.30, p = 0.10), live birth rate (RR 1.13, 95% CI 0.89-1.42, p = 0.32), multiple pregnancy rate (RR 0.58, 95% CI 0.19-1.73, p = 0.33) and abortion rate (RR 1.26, 95% CI 0.86-1.84, p = 0.23) between the two groups.

WHAT IS NEW AND CONCLUSION

CC combined with MET has an advantage in improving the clinical pregnancy rate compared to CC alone; however, there is no significant difference in the rate of ovulation. For better management of PCOS, a high-quality RCT is needed to demonstrate the safety of the combination.

Metabolic syndrome in obesity: treatment success and adverse pregnancy outcomes with ovulation induction in polycystic ovary syndrome

BACKGROUND

Obesity is common in women with polycystic ovary syndrome. polycystic ovary syndrome and obesity are associated with reduced fertility. The effect of metabolic syndrome on the success of infertility treatment and pregnancy outcomes in women with polycystic ovary syndrome undergoing ovulation induction has not been investigated.

OBJECTIVE

The objectives of this study were to determine the associations of metabolic syndrome on the rate of live birth after ovulation induction and pregnancy complications in obese women with polycystic ovary syndrome and determine whether there is a difference in outcomes concerning specific medications used for ovulation induction.

STUDY DESIGN

This prospective cohort analysis used data collected from participants in the Pregnancy in Polycystic Ovary Syndrome II clinical trial conducted by the Reproductive Medicine Network. In the Pregnancy in Polycystic Ovary Syndrome II trial, 750 women with polycystic ovary syndrome and infertility were randomized to either clomiphene citrate or letrozole for ovulation induction for 1 to 5 cycles or until pregnancy occurred. Cox regression and modified Poisson regression, chi-square test, and Student t test or Wilcoxon test were used in this study. Outcomes of interest were rates of live birth and clinical pregnancy and pregnancy complications. Having metabolic syndrome was defined by the presence of at least 3 of 5 cardiometabolic risk factors (waist circumference of >88 cm, low high-density lipoprotein cholesterol of <50 mg/dL, triglycerides of ≥150 mg/dL, systolic blood pressure of ≥130 or diastolic blood pressure of ≥85 mm Hg, and fasting glucose of >100 mg/dL). In addition, we used a continuous metabolic syndrome z score. Body mass index categories were defined as normal (body mass index of <25 kg/m²), high (25 to 35 kg/m²), and very high (>35 kg/m²).

RESULTS

As illustrated in the Table, early pregnancy losses showed no difference by metabolic syndrome. Fewer women achieved a clinical pregnancy (20.5% vs 29.7%; P=.007) or had a live birth (16.5% vs 27%; P=.001) in the presence of metabolic syndrome. Early pregnancy losses showed no difference by metabolic syndrome status. However, at least 1 pregnancy complication occurred more often with metabolic syndrome: 61.9% (26 of 42 cases) with metabolic syndrome vs 44.4% (59 of 133 cases) (P=.05) without metabolic syndrome. Gestational diabetes mellitus (35.7% vs 18.2%; P=.02) and macrosomia (21.4% vs 8.3%; P=.02) were more common in the presence of metabolic syndrome. After adjustment for other potential confounders, the rate ratio for live births for a 1-unit change in the metabolic syndrome z score was 0.89 (95% confidence interval, 0.79-1.00; P=.04) for those whose body mass index was 25 to 35 kg/m². For the very high body mass index subgroup (>35 kg/m²), the independent effects of metabolic syndrome from obesity were harder to discern. The rate of live birth was higher with the use of letrozole, although metabolic syndrome had a different detrimental effect concerning the medication given. The overall incidence of pregnancy complications was high (approximately 49%) in the Pregnancy in Polycystic Ovary Syndrome II trial and the 2 medications. Letrozole was associated with more obstetrical complications in the presence of metabolic syndrome, and clomiphene was associated with a lower rate of live birth rate when metabolic syndrome was present.

CONCLUSION

Metabolic syndrome is a risk factor that lowers the rate of live birth after ovulation for women with polycystic ovary syndrome, independent of obesity, and it is particularly associated with a lower rate of live birth for women using clomiphene compared with women using letrozole. In addition, metabolic syndrome is a risk factor for pregnancy complications for women with obesity using letrozole. Furthermore, having metabolic syndrome is a risk factor for gestational diabetes mellitus and macrosomia.

The function of metformin in endometrial receptivity (ER) of patients with polycyclic ovary syndrome (PCOS): a systematic review and meta-analysis

BACKGROUND

This meta-analysis summarizes evidence from studies using metformin (Met) to improve endometrial receptivity (ER) in women with PCOS.

METHODS

Following the PRISMA protocol, we conducted a comprehensive search of academic literature from various databases, including PubMed, EMbase and Cochrane libraries. Studies published in English before Jan 27, 2021, were recruited for primary screening. Data on endometrial thickness (EMT), endometrial artery resistance index (RI), clinical pregnancy rate (CPR) and miscarriage rate (MR) were extracted and analyzed.

RESULTS

Sixty-two eligible studies that included 6571 patients were evaluated in this meta-analysis. Primary indicators are EMT and endometrial aetery RI; secondary indicators include the clinical pregnancy rate and miscarriage rate. Metformin significantly increased EMT (SMD = 2.04, 95% CI (0.96,3.12),P = 0.0002) and reduced endometrial artery RI compared to the non-Met group (SMD = - 2.83, 95% CI: (- 5.06, - 0.59), P = 0.01). As expected, metformin also improved CPR and reduced MR in PCOS patients as a result, clinical pregnancy rate (risk ratio [RR] = 1.26, 95% CI: 1.11-1.43, P = 0.0003), and miscarriage rate (RR = 0.73, 95% CI:0.58-0.91, P = 0.006).

CONCLUSION

Metformin may improve endometrial receptivity (ER) in PCOS patients by increasing EMT and reducing endometrial artery RI. However, the level of most original studies was low, with small sample sizes. More large-scale, long-term RCTs with rigorous methodologies are needed.

To share or not to share data: how valid are trials evaluating first-line ovulation induction for polycystic ovary syndrome?

BACKGROUND

In our recent individual participant data (IPD) meta-analysis evaluating the effectiveness of first-line ovulation induction for polycystic ovary syndrome (PCOS), IPD were only available from 20 studies of 53 randomized controlled trials (RCTs). We noticed that the summary effect sizes of meta-analyses of RCTs without IPD sharing were different from those of RCTs with IPD sharing. Granting access to IPD for secondary analysis has implications for promoting fair and transparent conduct of RCTs. It is, however, still common for authors to choose to withhold IPD, limiting the impact of and confidence in the results of RCTs and systematic reviews based on aggregate data.

OBJECTIVE AND RATIONALE

We performed a meta-epidemiologic study to elucidate if RCTs without IPD sharing have lower quality and more methodological issues than those with IPD sharing in an IPD meta-analysis evaluating first-line ovulation induction for PCOS.

SEARCH METHODS

We included RCTs identified for the IPD meta-analysis. We dichotomized RCTs according to whether they provided IPD (shared group) or not (non-shared group) in the IPD meta-analysis. We restricted RCTs to full-text published trials written in English.

We assessed and compared RCTs in the shared and non-shared groups on the following criteria: Risk of Bias (RoB 2.0), GRADE approach, adequacy of trial registration; description of statistical methods and reproducibility of univariable statistical analysis; excessive similarity or difference in baseline characteristics that is not compatible with chance; and other miscellaneous methodological issues.

OUTCOMES

In total, 45 trials (8697 women) were included in this study. IPD were available from 17 RCTs and 28 trials were categorized as the non-shared IPD group. Pooled risk rates obtained from the shared and non-shared groups were different. Overall low risk of bias was associated with 13/17 (76%) of shared RCTs versus 7/28 (25%) of non-shared RCTs. For RCTs that started recruitment after 1 July 2005, adequate trial registration was found in 3/9 (33%) of shared IPD RCTs versus 0/16 (0%) in non-shared RCTs. In total, 7/17 (41%) of shared RCTs and 19/28 (68%) of non-shared RCTs had issues with the statistical methods described. The median (range) of inconsistency rate per study, between reported and reproduced analyses for baseline variables, was 0% (0–92%) (6 RCTs applicable) in the shared group and 54% (0–100%) (13 RCTs applicable) in the non-shared group. The median (range) of inconsistency rate of univariable statistical results for the outcome(s) per study was 0% (0–63%) (14 RCTs applicable) in the shared group and 44% (0–100%) (24 RCTs applicable) in the non-shared group. The distributions of simulation-generated P-values from comparisons of baseline continuous variables between intervention and control arms suggested that RCTs in the shared group are likely to be consistent with properly conducted randomization (P = 0.163), whereas this was not the case for the RCTs in the non-shared group (P = 4.535 × 10−8).

WIDER IMPLICATIONS

IPD meta-analysis on evaluating first-line ovulation induction for PCOS preserves validity and generates more accurate estimates of risk than meta-analyses using aggregate data, which enables more transparent assessments of benefits and risks. The availability of IPD and the willingness to share these data may be a good indicator of quality, methodological soundness and integrity of RCTs when they are being considered for inclusion in systematic reviews and meta-analyses.

Pathophysiological roles of chronic low-grade inflammation mediators in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common hormonal imbalance disease in reproductive-aged women. Its basic characteristics are ovulatory dysfunction and ovarian overproduction of androgens that lead to severe symptoms such as insulin resistance, hirsutism, infertility, and acne. Notwithstanding the disease burden, its underlying mechanisms remain unknown, and no causal therapeutic exists. In recent years, further studies showed that inflammation processes are involved in ovulation and play a key role in ovarian follicular dynamics. Visceral adipose tissue can cause inflammatory response and maintenance of the inflammation state in adipocytes by augmented production of inflammatory cytokines, monocyte chemoattractant proteins, and recruitment of the immune cell. Therefore, the PCOS can be related to a low-grade inflammation state and inflammatory markers. Investigating the inflammatory processes and mediators that contribute to the commencement and development of PCOS can be a critical step for better understanding the pathophysiology of the disease and its treatment through inhibition or control of related pathways. In the present review, we discuss the pathophysiological roles of chronic low-grade inflammation mediators including inflammasome-related cytokines, interleukin-1β (IL-1β), and IL-18 in PCOS development.

First-line ovulation induction for polycystic ovary syndrome: an individual participant data meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most frequent cause of anovulatory infertility. In women with PCOS, effective ovulation induction serves as an important first-line treatment for anovulatory infertility. Individual participant data (IPD) meta-analysis is considered as the gold standard for evidence synthesis which provides accurate assessments of outcomes from primary randomised controlled trials (RCTs) and allows additional analyses for time-to-event outcomes. It also facilitates treatment-covariate interaction analyses and therefore offers an opportunity for personalised medicine.

OBJECTIVE AND RATIONALE

We aimed to evaluate the effectiveness of different ovulation induction agents, in particular letrozole alone and clomiphene citrate (CC) plus metformin, as compared to CC alone, as the first-line choice for ovulation induction in women with PCOS and infertility, and to explore interactions between treatment and participant-level baseline characteristics.

SEARCH METHODS

We searched electronic databases including MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials up to 20 December 2018. We included RCTs comparing the following interventions with each other or placebo/no treatment in women with PCOS and infertility: CC, metformin, CC plus metformin, letrozole, gonadotrophin and tamoxifen. We excluded studies on treatment-resistant women. The primary outcome was live birth. We contacted the investigators of eligible RCTs to share the IPD and performed IPD meta-analyses. We assessed the risk of bias by using the Cochrane risk of bias tool for RCTs.

OUTCOMES

IPD of 20 RCTs including 3962 women with PCOS were obtained. Six RCTs compared letrozole and CC in 1284 women. Compared with CC, letrozole improved live birth rates (3 RCTs, 1043 women, risk ratio [RR] 1.43, 95% confidence interval [CI] 1.17-1.75, moderate-certainty evidence) and clinical pregnancy rates (6 RCTs, 1284 women, RR 1.45, 95% CI 1.23-1.70, moderate-certainty evidence) and reduced time-to-pregnancy (6 RCTs, 1235 women, hazard ratio [HR] 1.72, 95% CI 1.38-2.15, moderate-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline serum total testosterone levels and treatment effects on live birth (interaction RR 1.29, 95% CI 1.01-1.65). Eight RCTs compared CC plus metformin to CC alone in 1039 women. Compared with CC alone, CC plus metformin might improve clinical pregnancy rates (8 RCTs, 1039 women, RR 1.18, 95% CI 1.00-1.39, low-certainty evidence) and might reduce time-to-pregnancy (7 RCTs, 898 women, HR 1.25, 95% CI 1.00-1.57, low-certainty evidence), but there was insufficient evidence of a difference on live birth rates (5 RCTs, 907 women, RR 1.08, 95% CI 0.87-1.35, low-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline insulin levels and treatment effects on live birth in the comparison between CC plus metformin and CC (interaction RR 1.03, 95% CI 1.01-1.06).

WIDER IMPLICATIONS

In women with PCOS, letrozole improves live birth and clinical pregnancy rates and reduces time-to-pregnancy compared to CC and therefore can be recommended as the preferred first-line treatment for women with PCOS and infertility. CC plus metformin may increase clinical pregnancy and may reduce time-to-pregnancy compared to CC alone, while there is insufficient evidence of a difference on live birth. Treatment effects of letrozole are influenced by baseline serum levels of total testosterone, while those of CC plus metformin are affected by baseline serum levels of insulin. These interactions between treatments and biomarkers on hyperandrogenaemia and insulin resistance provide further insights into a personalised approach for the management of anovulatory infertility related to PCOS.

Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia occurs secondary to insulin resistance and is associated with an increased biochemical risk profile for cardiovascular disease and an increased prevalence of diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating PCOS-related anovulation. This is an update of Morley 2017 and only includes studies on metformin.

OBJECTIVES

To evaluate the effectiveness and safety of metformin in combination with or in comparison to clomiphene citrate (CC), letrozole and laparoscopic ovarian drilling (LOD) in improving reproductive outcomes and associated gastrointestinal side effects for women with PCOS undergoing ovulation induction.

SEARCH METHODS

We searched the following databases from inception to December 2018: Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL. We searched registers of ongoing trials and reference lists from relevant studies.

SELECTION CRITERIA

We included randomised controlled trials of metformin compared with placebo, no treatment, or in combination with or compared with CC, letrozole and LOD for women with PCOS subfertility.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility and bias. Primary outcomes were live birth rate and gastrointestinal adverse effects. Secondary outcomes included other pregnancy outcomes and ovulation. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I² statistic and reported quality of the evidence for primary outcomes and reproductive outcomes using GRADE methodology.

MAIN RESULTS

We included 41 studies (4552 women). Evidence quality ranged from very low to moderate based on GRADE assessment. Limitations were risk of bias (poor reporting of methodology and incomplete outcome data), imprecision and inconsistency. Metformin versus placebo or no treatment The evidence suggests that metformin may improve live birth rates compared with placebo (OR 1.59, 95% CI 1.00 to 2.51; I² = 0%; 4 studies, 435 women; low-quality evidence). For a live birth rate of 19% following placebo, the live birth rate following metformin would be between 19% and 37%. The metformin group probably experiences more gastrointestinal side effects (OR 4.00, 95% CI 2.63 to 6.09; I² = 39%; 7 studies, 713 women; moderate-quality evidence). With placebo, the risk of gastrointestinal side effects is 10% whereas with metformin this risk is between 22% and 40%. There are probably higher rates of clinical pregnancy (OR 1.98, 95% CI 1.47 to 2.65; I² = 30%; 11 studies, 1213 women; moderate-quality evidence). There may be higher rates of ovulation with metformin (OR 2.64, 95% CI 1.85 to 3.75; I² = 61%; 13 studies, 684 women; low-quality evidence). We are uncertain about the effect on miscarriage rates (OR 1.08, 95% CI 0.50 to 2.35; I² = 0%; 4 studies, 748 women; low-quality evidence). Metformin plus CC versus CC alone We are uncertain if metformin plus CC improves live birth rates compared to CC alone (OR 1.27, 95% CI 0.98 to 1.65; I² = 28%; 10 studies, 1219 women; low-quality evidence), but gastrointestinal side effects are probably more common with combined therapy (OR 4.26, 95% CI 2.83 to 6.40; I² = 8%; 6 studies, 852 women; moderate quality evidence). The live birth rate with CC alone is 24%, which may change to between 23% to 34% with combined therapy. With CC alone, the risk of gastrointestinal side effects is 9%, which increases to between 21% to 37% with combined therapy. The combined therapy group probably has higher rates of clinical pregnancy (OR 1.62, 95% CI 1.32 to 1.99; I² = 31%; 19 studies, 1790 women; moderate-quality evidence). The combined group may have higher rates of ovulation (OR 1.65, 95% CI 1.35 to 2.03; I² = 63%;21 studies, 1568 women; low-quality evidence). There was no clear evidence of an effect on miscarriage (OR 1.35, 95% CI 0.91 to 2.00; I² = 0%; 10 studies, 1206 women; low-quality evidence). Metformin versus CC When all studies were combined, findings for live birth were inconclusive and inconsistent (OR 0.71, 95% CI 0.49 to 1.01; I² = 86%; 5 studies, 741 women; very low-quality evidence). In subgroup analysis by obesity status, obese women had a lower birth rate in the metformin group (OR 0.30, 95% CI 0.17 to 0.52; 2 studies, 500 women), while the non-obese group showed a possible benefit from metformin, with high heterogeneity (OR 1.71, 95% CI 1.00 to 2.94; I² = 78%, 3 studies, 241 women; very low-quality evidence). However, due to the very low quality of the evidence we cannot draw any conclusions. Among obese women taking metformin there may be lower rates of clinical pregnancy (OR 0.34, 95% CI 0.21 to 0.55; I² = 0%; 2 studies, 500 women; low-quality evidence) and ovulation (OR 0.29, 95% CI 0.20 to 0.43; I² = 0%; 2 studies, 500 women; low-quality evidence) while among non-obese women, the metformin group may have more pregnancies (OR 1.56, 95% CI 1.06 to 2.29; I² = 26%; 6 studies, 530 women; low-quality evidence) and no clear difference in ovulation rates (OR 0.80, 95% CI 0.52 to 1.25; I² = 0%; 5 studies, 352 women; low-quality evidence). We are uncertain whether there is a difference in miscarriage rates between the groups (overall: OR 0.92, 95% CI 0.51 to 1.66; I² = 36%; 6 studies, 781 women; low-quality evidence) and no studies reported gastrointestinal side effects.

AUTHORS' CONCLUSIONS

Our updated review suggests that metformin may be beneficial over placebo for live birth however, more women probably experience gastrointestinal side effects. We are uncertain if metformin plus CC improves live birth rates compared to CC alone, but gastrointestinal side effects are probably increased with combined therapy. When metformin was compared with CC, data for live birth were inconclusive, and the findings were limited by lack of evidence. Results differed by body mass index (BMI), emphasising the importance of stratifying results by BMI. No studies reported gastrointestinal side effects in this comparison. Due to the low quality of the evidence, we are uncertain of the effect of metformin on miscarriage in all three comparisons.

Effect of clomiphene citrate on endometrial thickness, ovulation, pregnancy and live birth in anovulatory women: systematic review and meta-analysis

OBJECTIVES

To compare the impact of clomiphene citrate (CC) vs other drug regimens on mid-cycle endometrial thickness (EMT), ovulation, pregnancy and live birth rates in women with World Health Organization (WHO) group II ovulatory disorders.

METHODS

We searched MEDLINE, EMBASE, Scopus, Web of Science, The Cochrane Central Register of Clinical Trials (CENTRAL) and the non-MEDLINE subset of PubMed from inception to December 2016 and cross-checked references of relevant articles. We included only randomized controlled trials (RCTs) comparing CC used alone vs other drug regimens for ovulation induction in women with WHO group II anovulation. Outcomes were mid-cycle EMT, ovulation, pregnancy and live birth rates. We pooled weighted mean differences (WMD) with 95% confidence intervals (CI) for continuous variables (EMT) and risk ratios (RR) with 95% CI for binary variables (ovulation, pregnancy and live birth rates).

RESULTS

We retrieved 1718 articles of which 33 RCTs (4349 women, 7210 ovulation induction cycles) were included. In 15 RCTs that compared CC with letrozole, EMT was lower in the CC group (1957 women, 3892 cycles; WMD, -1.39; 95% CI, -2.27 to -0.51; I²  = 100%), ovulation rates after CC and letrozole were comparable (1710 women, 3217 cycles; RR, 0.97; 95% CI, 0.90-1.04; I²  = 47%), while CC led to a lower pregnancy rate (1957 women, 3892 cycles; RR, 0.78; 95% CI, 0.63-0.95; I²  = 43%) and a lower live birth rate (RR, 0.70; 95% CI, 0.49-0.98; I²  = 35%). In two RCTs that compared CC with CC plus metformin, EMT, ovulation and pregnancy rates were comparable (101 women, 140 cycles; WMD, -0.23; 95% CI, -0.92 to 0.45; I²  = 78%; RR, 0.84; 95% CI, 0.67-1.06; I²  = 0%; and RR, 0.79; 95% CI, 0.33-1.87; I²  = 0%). In three studies that compared CC with CC plus N-acetyl cysteine (NAC), EMT was lower in the CC group (340 women, 300 cycles; WMD, -1.51; 95% CI, -1.98 to -1.04; I²  = 45%). In two studies that compared CC with CC + nitric oxide (NO) donor, EMT was lower in the CC group (120 women, 304 cycles; WMD, -1.75; 95% CI, -2.08 to -1.41; I²  = 0%). Compared with CC plus NO donor or NAC, CC showed statistically significant lower ovulation and pregnancy rates. Compared with tamoxifen in three studies, CC showed a tendency towards lower EMT (571 women, 844 cycles; WMD, -1.34; 95% CI, -2.70 to 0.01; I²  = 96%) with comparable ovulation and pregnancy rates.

CONCLUSIONS

In women with WHO group II ovulatory disorders, ovulation induction with CC might result in lower EMT than other ovulation induction regimens. Whether the lower EMT caused the lower pregnancy and live birth rates remains to be elucidated. Letrozole seems to be beneficial for these women. However, our findings should be interpreted with caution as the quality of evidence was very low. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

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, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia occurs secondary to insulin resistance and is associated with increased risk of cardiovascular disease and diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating PCOS-related anovulation.

OBJECTIVES

To evaluate the effectiveness and safety of insulin-sensitising drugs in improving reproductive and metabolic outcomes for women with PCOS undergoing ovulation induction.

SEARCH METHODS

We searched the following databases from inception to January 2017: Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL. We searched registers of ongoing trials and reference lists from relevant studies.

SELECTION CRITERIA

We included randomised controlled trials of insulin-sensitising drugs compared with placebo, no treatment, or an ovulation-induction agent for women with oligo and anovulatory PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility and bias. Primary outcomes were live birth rate and gastrointestinal adverse effects. Secondary outcomes included other pregnancy outcomes, menstrual frequency and metabolic effects. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I2 statistic and reported quality of the evidence for primary outcomes using GRADE methodology.

MAIN RESULTS

We assessed the interventions metformin, clomiphene citrate, metformin plus clomiphene citrate, D-chiro-inositol, rosiglitazone and pioglitazone. We compared these with each other, placebo or no treatment. We included 48 studies (4451 women), 42 of which investigated metformin (4024 women). Evidence quality ranged from very low to moderate. Limitations were risk of bias (poor reporting of methodology and incomplete outcome data), imprecision and inconsistency. Metformin versus placebo or no treatmentThe evidence suggests that metformin may improve live birth rates compared with placebo (OR 1.59, 95% CI 1.00 to 2.51, 4 studies, 435 women, I2 = 0%, low-quality evidence). The metformin group experienced more gastrointestinal side effects (OR 4.76, 95% CI 3.06 to 7.41, 7 studies, 670 women, I2 = 61%, moderate-quality evidence) but had higher rates of clinical pregnancy (OR 1.93, 95% CI 1.42 to 2.64, 9 studies, 1027 women, I2 = 43%, moderate-quality evidence), ovulation (OR 2.55, 95% CI 1.81 to 3.59, 14 studies, 701 women, I2 = 58%, moderate-quality evidence) and menstrual frequency (OR 1.72, 95% CI 1.14 to 2.61, 7 studies, 427 women, I2 = 54%, low-quality evidence). There was no clear evidence of a difference in miscarriage rates (OR 1.08, 95% CI 0.50 to 2.35, 4 studies, 748 women, I2 = 0%, low-quality evidence). Metformin plus clomiphene citrate versus clomiphene citrate alone There was no conclusive evidence of a difference between the groups in live birth rates (OR 1.21, 95% CI 0.92 to 1.59, 9 studies, 1079 women, I2 = 20%, low-quality evidence), but gastrointestinal side effects were more common with combined therapy (OR 3.97, 95% CI 2.59 to 6.08, 3 studies, 591 women, I2 = 47%, moderate-quality evidence). However, the combined therapy group had higher rates of clinical pregnancy (OR 1.59, 95% CI 1.27 to 1.99, 16 studies, 1529 women, I2 = 33%, moderate-quality evidence) and ovulation (OR 1.57, 95% CI 1.28 to 1.92, 21 studies, 1624 women, I2 = 64%, moderate-quality evidence). There was a statistically significant difference in miscarriage rate per woman, with higher rates in the combined therapy group (OR 1.59, 95% CI 1.03 to 2.46, 9 studies, 1096 women, I2 = 0%, low-quality evidence) but this is of uncertain clinical significance due to low-quality evidence, and no clear difference between groups when we analysed miscarriage per pregnancy (OR 1.30, 95% CI 0.80 to 2.12, 8 studies; 400 pregnancies, I2 = 0%, low-quality evidence). Metformin versus clomiphene citrateWhen all studies were combined, findings for live birth were inconclusive and inconsistent (OR 0.71, 95% CI 0.49 to 1.01, 5 studies, 741 women, I2 = 86%, very low-quality evidence). In subgroup analysis by obesity status, obese women had a lower birth rate in the metformin group (OR 0.30, 95% CI 0.17 to 0.52, 2 studies, 500 women, I2 = 0%, very low-quality evidence), while data from the non-obese group showed a possible benefit from metformin, with high heterogeneity (OR 1.71, 95% CI 1.00 to 2.94, 3 studies, 241 women, I2 = 78%, very low-quality evidence). Similarly, among obese women taking metformin there were lower rates of clinical pregnancy (OR 0.34, 95% CI 0.21 to 0.55, 2 studies, 500 women, I2 = 0%, very low-quality evidence) and ovulation (OR 0.29, 95% CI 0.20 to 0.43 2 studies, 500 women, I2 = 0%, low-quality evidence) while among non-obese women, the metformin group had more pregnancies (OR 1.56, 95% CI 1.05 to 2.33, 5 studies, 490 women, I2 = 41%, very low-quality evidence) and no clear difference in ovulation rates (OR 0.81, 95% CI 0.51 to 1.28, 4 studies, 312 women, low-quality evidence, I2=0%). There was no clear evidence of a difference in miscarriage rates (overall: OR 0.92, 95% CI 0.50 to 1.67, 5 studies, 741 women, I2 = 52%, very low-quality evidence). D-chiro-inositol (2 studies), rosiglitazone (1 study) or pioglitazone (1 study) versus placebo or no treatmentWe were unable to draw conclusions regarding other insulin-sensitising drugs as no studies reported primary outcomes.

AUTHORS' CONCLUSIONS

Our updated review suggests that metformin alone may be beneficial over placebo for live birth, although the evidence quality was low. When metformin was compared with clomiphene citrate, data for live birth were inconclusive, and our findings were limited by lack of evidence. Results differed by body mass index (BMI), emphasising the importance of stratifying results by BMI. An improvement in clinical pregnancy and ovulation suggests that clomiphene citrate remains preferable to metformin for ovulation induction in obese women with PCOS.An improved clinical pregnancy and ovulation rate with metformin and clomiphene citrate versus clomiphene citrate alone suggests that combined therapy may be useful although we do not know whether this translates into increased live births. Women taking metformin alone or with combined therapy should be advised that there is no evidence of increased miscarriages, but gastrointestinal side effects are more likely.

Treatment strategies for women with WHO group II anovulation: systematic review and network meta-analysis

OBJECTIVE

To compare the effectiveness of alternative first line treatment options for women with WHO group II anovulation wishing to conceive.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, and Embase, up to 11 April 2016.

STUDY SELECTION

Randomised controlled trials comparing eight ovulation induction treatments in women with WHO group II anovulation: clomiphene, letrozole, metformin, clomiphene and metformin combined, tamoxifen, gonadotropins, laparoscopic ovarian drilling, and placebo or no treatment. Study quality was measured on the basis of the methodology and categories described in the Cochrane Collaboration Handbook. Pregnancy, defined preferably as clinical pregnancy, was the primary outcome; live birth, ovulation, miscarriage, and multiple pregnancy were secondary outcomes.

RESULTS

Of 2631 titles and abstracts initially identified, 54 trials reporting on 7173 women were included. All pharmacological treatments were superior to placebo or no intervention in terms of pregnancy and ovulation. Compared with clomiphene alone, both letrozole and the combination of clomiphene and metformin showed higher pregnancy rates (odds ratio 1.69, 95% confidence interval 1.33 to 2.14; 1.71, 1.28 to 2.27; respectively). Letrozole led to higher live birth rates when compared with clomiphene alone (1.67, 1.11 to 2.49). Metformin led to lower multiple pregnancy rates compared with clomiphene alone (0.22, 0.05 to 0.93).

CONCLUSIONS

In women with WHO group II anovulation, letrozole and the combination of clomiphene and metformin are superior to clomiphene alone in terms of pregnancy. Compared with clomiphene alone, letrozole is the only treatment showing a significantly higher rate of live birth.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015027579.

READERS' NOTE

This is the second version of this paper. The original version was corrected following the retraction of two studies and removal of another which were ineligible (references 40, 41, and 75 of the original paper). These studies are not shown in this version. A tracked changes version of the original version is attached as a supplementary file to the correction notice, which explains the issue further.

Clomiphene citrate, metformin or a combination of both as the first line ovulation induction drug for Asian Indian women with polycystic ovarian syndrome: A randomized controlled trial

AIM

To compare clomiphene citrate (CC), metformin or the combination of CC and metformin as the first line ovulation induction drug in Asian Indian women with polycystic ovary syndrome (PCOS).

METHODS

One hundred and five newly diagnosed, treatment naive PCOS women were recruited. They were randomized into any of the three groups: Group I (CC 50-150 mg/day), Group II (metformin 1700 mg/day), and Group III (CC + metformin in similar dosage to Groups I and II). Patients underwent follicular monitoring and advice on timed intercourse. The study period was 6 months, or till pregnant, or till CC resistant. Primary outcome studied was live birth rate (LBR). Secondary outcomes were ovulation rate, pregnancy rate, and early pregnancy loss rate.

RESULTS

There was no significant difference among the groups in baseline characteristics and biochemical parameters. LBR was 41.6%, 37.5%, and 28.1%, respectively in Groups III, II, and I. Group III (CC + metformin) had the highest ovulation (83.3%), pregnancy (50%), and LBRs (41.6%). Group II (metformin) was as good as Group I (CC) in all the outcomes. CC + metformin (Group III) had statistically significantly higher ovulation rate as compared to CC alone (Group I) (P = 0.03; odds ratio: 95% confidence interval: 3.888 [1.08-13.997]).

CONCLUSION

Thus, our study shows that metformin was as good as CC in terms of "LBR" and the combination of CC and metformin gave the highest ovulation and LBR.

Ovulation induction

Before initiating ovulation induction, it is important to evaluate the underlying cause of a patient's anovulation and to make lifestyle modifications or treat underlying medical conditions, as appropriate. Here, ovulation induction agents are discussed with attention to their pharmacology, indications for use, therapy regimens, and efficacy. Adjuvant therapies and appropriate monitoring are also reviewed.

Direct effects of metformin in the endometrium: a hypothetical mechanism for the treatment of women with PCOS and endometrial carcinoma

Although a number of in vitro studies have demonstrated the antiproliferative, anti-invasive, and antimetastatic effects of metformin in multiple cancer cell types, its cellular and molecular mechanisms of anti-cancer action in the endometrium of women with polycystic ovary syndrome (PCOS) have not yet been fully elucidated. Organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs) are known to be involved in metformin uptake and excretion in cells. In this article, we discuss the novel therapeutic possibilities for early-stage endometrial carcinoma (EC) in women with PCOS focusing on metformin, which might have a direct effect in the endometrium through the OCTs and MATEs. We then review the molecular mechanism(s) of the action of metformin in the endometrium and highlight possible mechanistic insights into the inhibition of cell proliferation and tumor growth and, ultimately, the reversal of early-stage EC into normal endometria in women with PCOS.

Use of clomiphene citrate in infertile women: a committee opinion

This committee opinion describes the use of clomiphene citrate, including indications, use, monitoring, and side effects. There is also a discussion of adjuvants and alternatives to clomiphene citrate therapy.

The evaluation and treatment of hirsute women

Hirsutism in women is defined as an excess of body hair in the androgen-sensitive skin regions. The different genetic backgrounds of various populations may affect the causes of hirsutism. In fact, the most important reason for investigation is to identify those women with androgen-secreting tumors, since they require different therapy. Hirsutism may have various causes, such as polycystic ovary syndrome, enzyme defects in adrenal steroid biosynthesis, Cushing's syndrome, acromegaly, ovarian or adrenal tumors, or it may be idiopathic. In most patients, hirsutism is associated with hyperandrogenemia and the most common cause of androgen excess is polycystic ovary syndrome. Androgen-secreting tumors should be suspected when the onset and progression of hirsutism is rapid and/or when it is associated with virilization. Patients should be informed about the type and duration of therapy. The selection of drug/drugs depends on the severity of the hirsutism, associated conditions such as menstrual irregularities, systemic disorders such as diabetes mellitus, hypertension and any contraindication to possible therapeutic agents. Diane(R) 35 is the most common drug used for the suppression of ovarian androgen production. Peripheral blockade of androgen actions, by using spironolactone, finasteride or flutamide on the skin, is also effective in the treatment of hirsutism.

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.

Is metformin indicated as primary ovulation induction agent in women with PCOS? A systematic review and meta-analysis

BACKGROUND

A recent meta-analysis has proven that metformin (M) is highly effective for ovulation induction in the clomiphene citrate (CC)-resistant patient. There is uncertainty whether M should be introduced as a primary ovulation induction agent in polycystic ovarian syndrome (PCOS).

METHODS

We conducted a systematic review and meta-analysis to establish if M is better when given alone or in combination with CC (CC+M) when compared with CC alone. This systematic review studied live birth delivery rate as the primary outcome.

RESULTS

We identified 14 prospective trials. Analysis of these results showed a reduction in the live birth rate in the group of patients treated only with M when compared with CC alone (OR = 0.48, 95% CI 0.31-0.73, p = 0.0006). An increase in ovulation (OR = 1.6, 95% CI 1.2-2.1, p = 0.0009) and pregnancy rate (OR = 1.3, 95% CI 1.0-1.6, p = 0.05) with CC+M when compared with CC alone was reported, but no difference was found when live birth rate was analyzed (OR = 1.1, 95% CI 0.8-1.5, p = 0.61).

CONCLUSION

CC alone is superior to M alone regarding live birth rate and ovulation. The combination (CC+M) is superior to CC alone as a primary method for ovulation induction and to achieve pregnancy in PCOS. However, when addressing live birth rate, no statistically significant difference could be demonstrated. Because of the side effects profile and contraindications of M, we believe M should not be indicated as a primary ovulation induction agent in women with PCOS.

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 anovulation, hyperandrogaenemia and insulin resistance. Hyperinsulinaemia is associated with an increase in cardiovascular risk and the development of diabetes mellitus. If insulin sensitising agents such as metformin are effective in treating features of PCOS, then they could have wider health benefits than just treating the symptoms of the syndrome.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register (searched September 2008), the Cochrane Central Register of Controlled Trials (Cochrane Library, third Quarter 2008), CINAHL (searched September 2008), MEDLINE (January 1966 to September 2008), and EMBASE (January 1985 to September 2008). All searches were rerun 13 August 2009 17 RCTs were located and await classification.

SELECTION CRITERIA

Randomised controlled trials which investigated the effect of insulin sensitising drugs compared with either placebo or no treatment, or compared with an ovulation induction agent.

DATA COLLECTION AND ANALYSIS

Thirty one trials (2537 women) were included for analysis, 27 of them using metformin and involving 2150 women.

MAIN RESULTS

There is no evidence that metformin improves live birth rates whether it is used alone (Pooled OR = 1.00, 95% CI 0.16 to 6.39) or in combination with clomiphene (Pooled OR = 1.48, 95% CI 1.12 to 1.95). However, clinical pregnancy rates are improved for metformin versus placebo (Pooled OR = OR 3.86, 95% C.I. 2.18 to 6.84) and for metformin and clomiphene versus clomiphene alone (Pooled OR =1.48, 95% C.I. 1.12 to 1.95) ). In the studies that compared metformin and clomiphene alone, there was no evidence of an improved live birth rate (OR= 0.67, 95% CI 0.44 to 1.02) but the pooled OR resulted in improved clinical pregnancy rate in in the clomiphene group (OR = 0.63 , 95% 0.43 to 0.92), although there was significant heterogeneity.There is also evidence that ovulation rates are improved with metformin in women with PCOS for metformin versus placebo (Pooled OR 2.12, 95% CI 1.50 to 3.0) and for metformin and clomiphene versus clomiphene alone (Pooled OR = 3.46, 95% CI 1.97 to 6.07).Metformin was also associated with a significantly higher incidence of gastrointestinal disturbance, but no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

In agreement with the previous review, metformin is still of benefit in improving clinical pregnancy and ovulation rates. However, there is 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 use of metformin in improving reproductive outcomes in women with PCOS appears to be limited.

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 anovulation, hyperandrogaenemia and insulin resistance. Hyperinsulinaemia is associated with an increase in cardiovascular risk and the development of diabetes mellitus. If insulin sensitising agents such as metformin are effective in treating features of PCOS, then they could have wider health benefits than just treating the symptoms of the syndrome.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register (searched September 2008), the Cochrane Central Register of Controlled Trials (Cochrane Library, third Quarter 2008), CINAHL (searched September 2008), MEDLINE (January 1966 to September 2008), and EMBASE (January 1985 to September 2008). All searches were rerun 13 August 2009 17 RCTs were located and await classification.

SELECTION CRITERIA

Randomised controlled trials which investigated the effect of insulin sensitising drugs compared with either placebo or no treatment, or compared with an ovulation induction agent.

DATA COLLECTION AND ANALYSIS

Thirty one trials (2537 women) were included for analysis, 27 of them using metformin and involving 2150 women.

MAIN RESULTS

There is no evidence that metformin improves live birth rates whether it is used alone (Pooled OR = 1.00, 95% CI 0.16 to 6.39) or in combination with clomiphene (Pooled OR = 1.48, 95% CI 1.12 to 1.95). However, clinical pregnancy rates are improved for metformin versus placebo (Pooled OR = OR 3.86, 95% C.I. 2.18 to 6.84) and for metformin and clomiphene versus clomiphene alone (Pooled OR =1.48, 95% C.I. 1.12 to 1.95) ). In the studies that compared metformin and clomiphene alone, there was no evidence of an improved live birth rate (OR= 0.67, 95% CI 0.44 to 1.02) but the pooled OR resulted in improved clinical pregnancy rate in in the clomiphene group (OR = 0.63 , 95% 0.43 to 0.92), although there was significant heterogeneity.There is also evidence that ovulation rates are improved with metformin in women with PCOS for metformin versus placebo (Pooled OR 2.12, 95% CI 1.50 to 3.0) and for metformin and clomiphene versus clomiphene alone (Pooled OR = 3.46, 95% CI 1.97 to 6.07).Metformin was also associated with a significantly higher incidence of gastrointestinal disturbance, but no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

In agreement with the previous review, metformin is still of benefit in improving clinical pregnancy and ovulation rates. However, there is 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 use of metformin in improving reproductive outcomes in women with PCOS appears to be limited.

WITHDRAWN: Insulin-sensitising drugs for polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterised by anovulation, hyperandrogaenemia and insulin resistance. Hyperinsulinaemia is associated with an increase in cardiovascular risk and the development of diabetes mellitus. If insulin sensitising agents such as metformin are effective in treating features of PCOS, then they could have wider health benefits than just treating the symptoms of the syndrome.

OBJECTIVES

To assess the effectiveness of insulin sensitising drugs in improving clinical and biochemical features of PCOS.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register (searched September 2008 ), the Cochrane Central Register of Controlled Trials (Cochrane Library, September 2008), MEDLINE (January 1966 to September 2008), and EMBASE (January 1985 to September 2008).

SELECTION CRITERIA

Randomised controlled trials which investigated the effect of insulin sensitising drugs compared with either placebo or no treatment, or compared with an ovulation induction agent.

DATA COLLECTION AND ANALYSIS

Thirty nine trials (3576 subjects) were included for analysis, 31 of them using metformin and involving 2625 participants.

MAIN RESULTS

Meta-analysis showed that metformin is effective in achieving ovulation in women with PCOS with odds ratios of 2.21(CI 1.57 to 3.10) for metformin versus placebo and 3.93(CI 2.32 to 6.65) for metformin and clomiphene versus clomiphene alone. An analysis of pregnancy rates suggests a significant treatment effect for metformin and clomiphene (OR 1.58, CI 1.20 to 2.07). Nevertheless, these benefits were not translated into live birth rates.Metformin has a significant effect in reducing fasting insulin levels (WMD -4.20 mIU/L, CI -7.68 to -0.73); however, the reduction was only significant in the non-obese group (BMI < 30 kg/m2). Treatment effect on serum testosterone concentration was observed; but the magnitude of the reduction was greater in the non-obese group compared with the obese group (WMD -1.79 versus. -0.30 nmol/L). Metformin has no effect on serum lipid profiles. Metformin was also associated with a significantly higher incidence of gastrointestinal disturbance, but no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

In agreement with the previous review, metformin is still of benefit in improving ovulation and pregnancy rates. However, metformin does not improve live birth whether it is used alone or in combination with clomiphene. In addition, metformin has limited effect on metabolic parameters, especially in obese women with PCOS. Therefore, the use of metformin in improvement of reproductive outcomes or in reducing the risk of developing metabolic syndrome in women with PCOS appears to be limited.

Clomiphene citrate, metformin or both as first-step approach in treating anovulatory infertility in patients with polycystic ovary syndrome (PCOS): a systematic review of head-to-head randomized controlled studies and meta-analysis

BACKGROUND

To date, no systematic review or meta-analysis has been published of direct head-to-head studies comparing clomiphene citrate (CC) vs. metformin, or the combination of both drugs as first-line therapy in anovulatory polycystic ovary syndrome (PCOS) patients seeking pregnancy. The aim of the current paper was to define, if possible, the best evidence-based recommendations regarding the use of CC and/or metformin as the initial treatment of PCOS women with anovulatory infertility.

DESIGN

Systematic review and meta-analysis of the head-to-head randomized controlled trials (RCTs) available in the literature.

METHODS

A bibliographic search was performed using the following bibliographic databases: Medline, EMBASE, Biological Abstracts, Cochrane Controlled Trials Register and Cochrane Database of Systematic Reviews. Reference lists of included studies, other relevant review articles and textbooks were checked for additional citations of interest.

RESULTS

Four head-to-head RCTs were identified and qualified for inclusion in the analysis. No difference in fertility improvement was observed comparing CC with metformin (OR = 1.22, 95% CI 0.23-6.55, P = 0.815), whereas a significant (P < 0.0001) heterogeneity was observed. Homogeneous data showed no difference in fertility improvement between the combination treatment and CC monotherapy (OR = 0.99, 95% CI 0.70-1.40, P = 0.982), but a significant difference in comparison with metformin monotherapy (OR = 0.23, 95% CI 0.14-0.37, P < 0.0001).

CONCLUSIONS

In PCOS patients with anovulatory infertility and not previously treated, the administration of metformin plus CC is not better than monotherapy (metformin alone or CC alone), whereas to date no specific recommendation can be given regarding the use of CC or metformin as first-step drug.

Effect of preconceptional metformin on abortion risk in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effect of pregestational metformin administration on abortion risk in polycystic ovary syndrome (PCOS) patients.

DESIGN

Systematic review and meta-analysis.

SETTING

Academic Department of Obstetrics and Gynecology in Italy.

PATIENT(S)

Women affected by PCOS receiving pregestational metformin.

INTERVENTION(S)

Systematic review of randomized controlled trials (RCTs) published up to June 2008 and subsequent meta-analysis.

MAIN OUTCOME MEASURE(S)

Abortion rate.

RESULT(S)

Seventeen RCTs were included in the final analysis. Overall, no effect of the metformin administration was detected on the abortion risk. No statistically significant effect of metformin on the abortion risk was observed in any comparison when subgrouping the RCTs according to received treatment.

CONCLUSION(S)

Metformin has no effect on the abortion risk in PCOS patients when administered before pregnancy.

Use of metformin in polycystic ovary syndrome: a meta-analysis

OBJECTIVE

To update the state of evidence on the efficacy of metformin, used either alone or in combination with clomiphene citrate in women with polycystic ovary syndrome, by examining three outcomes: ovulation, pregnancy, and live birth. Sources of heterogeneity among the published randomized controlled trials are systematically assessed.

DATA SOURCES

An electronic literature search was performed using MEDLINE, EMBASE, SCOPUS, CENTRAL, Cochrane, and U.S. Food and Drug Administration databases, restricted to studies conducted on humans and published in English.

METHODS OF STUDY SELECTION

Of the 406 potentially relevant articles identified, 17 met criteria for inclusion in the meta-analysis, rendering a total sample of 1,639 women. Study quality was examined in terms of randomization scheme, masking process, adequacy of allocation concealment, statistical power, and loss to follow-up; publication bias was also assessed. Meta-analytic procedures were used to compare metformin with placebo, and metformin plus clomiphene with clomiphene alone, for all study outcomes. Exploratory analyses were conducted to assess differences in treatment effects between clomiphene-resistant and nonresistant patients, obese and nonobese patients, and trials with long and short durations of follow-up.

TABULATION, INTEGRATION, AND RESULTS

Metformin improved the odds of ovulation in women with polycystic ovary syndrome when compared with placebo (odds ratio [OR] 2.94; 95% confidence interval [CI] 1.43-6.02; number-needed-to-treat 4.0) and appears more effective for non-clomiphene-resistant women. Metformin and clomiphene increased the likelihood of ovulation (OR 4.39; 95% CI 1.94-9.96; number-needed-to-treat 3.7) and pregnancy (OR 2.67; 95% CI 1.45-4.94; number-needed-to-treat 4.6) when compared with clomiphene alone, especially in clomiphene-resistant and obese women with polycystic ovary syndrome. These treatment effects were greater for trials with shorter follow-up.

CONCLUSION

Using all available evidence, this meta-analysis suggests that metformin increases the likelihood of ovulation and, in combination with clomiphene, increases the odds of both ovulation and pregnancy in women with polycystic ovary syndrome.

Comparison of clomiphene citrate, metformin, or the combination of both for first-line ovulation induction, achievement of pregnancy, and live birth in Asian women with polycystic ovary syndrome: a randomized controlled trial

OBJECTIVE

To determine the first-line medication to be used in anovulatory patients with polycystic ovary syndrome (PCOS) for ovulation induction and pregnancy achievement.

DESIGN

Randomized controlled trial.

SETTING

Infertility unit of a public hospital.

PATIENT(S)

One hundred fifteen newly diagnosed patients with PCOS based on ESHRE/ASRM criteria.

INTERVENTION(S)

These patients were assigned to three groups: group 1 (38 patients) received 500 mg of metformin three times a day; group 2 (39 patients) received clomiphene citrate (CC) at an incremental dose; group 3 (38 patients) received both medications.

MAIN OUTCOME MEASURE(S)

Rates of ovulation, pregnancy (PR), and live birth.

RESULT(S)

The ovulation rate was 23.7% in the metformin group, 59% in the CC group, and 68.4% in the combination treatment group. This was translated into a similar PR and live birth rate, which were higher in the CC and combination groups compared to the metformin group (PR: 7.9%, 15.4%, and 21.1%; live birth rate: 7.9%, 15.4%, and 18.4% in metformin, CC, and combination treatment groups, respectively), although statistically the differences were not significant. There were no multiple pregnancies and the rate of spontaneous first trimester loss was similar to the general population.

CONCLUSION(S)

Clomiphene citrate should be the first-line treatment for ovulation induction in anovulatory patients with PCOS.

The role of metformin in polycystic ovary syndrome: a systematic review

This meta-analysis evaluated the effectiveness of metformin in subfertile women with polycystic ovary syndrome (PCOS). Only randomized trials investigating the effectiveness of metformin and PCOS definition consistent with the Rotterdam consensus criteria, were eligible. Primary outcome was live birth rate. A literature search identified 27 trials. In therapy naïve women, we found no evidence of a difference in live birth rate when comparing metformin with clomifene citrate (CC) [relative risks (RR) 0.73; 95% confidence interval (CI) 0.51-1.1] or comparing metformin plus CC with CC (RR 1.0; 95% CI 0.82-1.3). In CC-resistant women, metformin plus CC led to higher live birth rates than CC alone (RR 6.4; 95% CI 1.2-35); metformin also led to higher live birth rates than laparoscopic ovarian drilling (LOD) (RR 1.6; 95% CI 1.1-2.5). We found no evidence for a positive effect of metformin on live birth when added to LOD (RR 1.3; 95% CI 0.39-4.0) or FSH (RR 1.6; 95% CI 0.95-2.9), or when co-administered in IVF (RR 1.5; 95% CI 0.92-2.5). In IVF, metformin led to fewer cases of ovarian hyperstimulation syndrome (OHSS) (RR 0.33; 95% CI 0.13-0.80). This meta-analysis demonstrates that CC is still first choice therapy for women with therapy naïve PCOS. In CC-resistant women, the combination of CC plus metformin is the preferred treatment option before starting with LOD or FSH. At present, there is no evidence of an improvement in live birth when adding metformin to LOD or FSH. In IVF, metformin leads to a reduced risk of OHSS.

Clomiphene, metformin, or both for infertility in the polycystic ovary syndrome

BACKGROUND

The polycystic ovary syndrome is a common cause of infertility. Clomiphene and insulin sensitizers are used alone and in combination to induce ovulation, but it is unknown whether one approach is superior.

METHODS

We randomly assigned 626 infertile women with the polycystic ovary syndrome to receive clomiphene citrate plus placebo, extended-release metformin plus placebo, or a combination of metformin and clomiphene for up to 6 months. Medication was discontinued when pregnancy was confirmed, and subjects were followed until delivery.

RESULTS

The live-birth rate was 22.5% (47 of 209 subjects) in the clomiphene group, 7.2% (15 of 208) in the metformin group, and 26.8% (56 of 209) in the combination-therapy group (P<0.001 for metformin vs. both clomiphene and combination therapy; P=0.31 for clomiphene vs. combination therapy). Among pregnancies, the rate of multiple pregnancy was 6.0% in the clomiphene group, 0% in the metformin group, and 3.1% in the combination-therapy group. The rates of first-trimester pregnancy loss did not differ significantly among the groups. However, the conception rate among subjects who ovulated was significantly lower in the metformin group (21.7%) than in either the clomiphene group (39.5%, P=0.002) or the combination-therapy group (46.0%, P<0.001). With the exception of pregnancy complications, adverse-event rates were similar in all groups, though gastrointestinal side effects were more frequent, and vasomotor and ovulatory symptoms less frequent, in the metformin group than in the clomiphene group.

CONCLUSIONS

Clomiphene is superior to metformin in achieving live birth in infertile women with the polycystic ovary syndrome, although multiple birth is a complication. (ClinicalTrials.gov number, NCT00068861 [ClinicalTrials.gov].).

Comparison of clomiphene citrate, metformin, or the combination of both for first-line ovulation induction and achievement of pregnancy in 154 women with polycystic ovary syndrome

OBJECTIVE

To determine which first-line medication is more effective in polycystic ovary syndrome (PCOS) patients for ovulation induction and pregnancy achievement and to verify whether any patient characteristic is associated with a better response to therapy.

DESIGN

Observational comparative study.

SETTING

Fertility clinic.

PATIENT(S)

One hundred fifty-four infertile women with oligomenorrhea and hyperandrogenism.

INTERVENTION(S)

Group 1 (56 patients) received clomiphene citrate (CC) 50 mg from days 5-9 of the cycle. Group 2 (57 patients) received 500 mg of metformin 3 times a day. Group 3 (41 patients) received both medications.

MAIN OUTCOME MEASURE(S)

Ovulation and pregnancy.

RESULT(S)

Patients receiving metformin alone had an increased ovulation rate compared with those receiving CC alone (75.4% vs. 50%). Patients on metformin had similar ovulation rates compared with those in the combination group (75.4% vs. 63.4%). Pregnancy rates were equivalent in the 3 groups. Response to metformin was independent of body weight and dose. Finally, nonsmoking predicted better ovulatory response overall as well as lower fasting glucose for CC and lower androgens for metformin.

CONCLUSION(S)

Metformin is better for ovulation induction than CC alone and equivalent for pregnancy achievement. We suggest that metformin can be used first for ovulation induction in patients with PCOS regardless of their weight and insulin levels because of its efficacy and known safety profile.

Pregnancy outcome after first-trimester exposure to metformin: a meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of pregnancy outcome after metformin use for polycystic ovary syndrome (PCOS), because the efficacy of metformin has been demonstrated in the treatment of infertility caused by PCOS, whereas the fetal safety of metformin has received very little attention, and the few studies addressing this issue are limited by small sample sizes.

DESIGN

Meta-analytic review.

SETTING

All pertinent studies in MEDLINE and EMBASE from 1966 to September 2004.

PATIENT(S)

Women with PCOS or diabetes.

INTERVENTION(S)

Exposure to metformin in the first trimester of pregnancy.

MAIN OUTCOME MEASURE(S)

Major malformations.

RESULT(S)

Eight studies were included in the meta-analysis, with an odds ratio of 0.50 (95% confidence interval, 0.15, 1.60). After adjustment for publication bias, metformin treatment in the first trimester was associated with a statistically significant 57% protective effect. After pooling the studies, the malformation rate in the disease-matched control group was approximately 7.2%, statistically significantly higher than the rate found in the metformin group (1.7%).

CONCLUSION(S)

On the basis of the limited data available today, there is no evidence of an increased risk for major malformations when metformin is taken during the first trimester of pregnancy. Large studies are needed to corroborate these preliminary results.

Use of Metformin for Ovulation Induction in Women Who Have Polycystic Ovary Syndrome With or Without Evidence of Insulin Resistance

OBJECTIVE

To determine whether women with polycystic ovary syndrome (PCOS) and abnormal insulin levels treated with metformin had different rates of ovulation and pregnancy from women with PCOS and normal insulin levels.

METHODS

The outcomes of treatment with metformin in 146 infertile women with PCOS were analyzed using a retrospective cohort study design. Baseline characteristics and initial blood work results were recorded. The follow-up period was three months, and the primary outcome was ovulation.

RESULTS

Of the 146 women with PCOS, one third had elevated fasting insulin levels. After treatment with metformin, cumulative rates of ovulation were similar in women with elevated fasting serum insulin levels (48.8%) and those with normal levels (44.7%). Rates of ovulation were also similar in women with normal and abnormal glucose to insulin ratios. There was no difference in cumulative pregnancy rates based on fasting insulin levels. A fasting insulin level above 20 mU/L correlated with an abnormal glucose to insulin ratio (98%).

CONCLUSION

In anovulatory women with PCOS, fasting insulin levels and glucose to insulin ratios do not predict the ovulatory response to metformin.

Metformin administration and laparoscopic ovarian drilling improve ovarian response to clomiphene citrate (CC) in oligo-anovulatory CC-resistant women with polycystic ovary syndrome

OBJECTIVE

To compare the efficacy of clomiphene citrate (CC) administration for ovulation induction in CC-resistant oligo-ovulatory women with polycystic ovary syndrome (PCOS) after metformin treatment or laparoscopic ovarian drilling (LOD). Design Prospective controlled study.

PATIENTS

Twenty-eight overweight oligo-amenorrhoeic women with PCOS who were still anovulatory after metformin administration (group A, n = 8) or LOD (group B, n = 20).

METHODS

Treatment with CC 150 mg/day for 5 days from the third to the seventh day of a progesterone-induced uterine bleeding for 6 months.

MEASUREMENTS

The ovulation, pregnancy, abortion and live-birth rates were evaluated in each group.

RESULTS

The subjects of groups A and B were studied for a total of 36 and 74 cycles, respectively. At the end of the study, no differences in ovulation [11/36 (30.6%) vs. 23/74 (31.1%); P = 0.96], pregnancy [6/36 (16.7%) vs. 12/74 (16.2%); P = 0.95], abortion [2/6 (33.3%) vs. 5/12 (41.7%); P = 1.00] and the live-birth [4/6 (66.7%) vs. 7/12 (58.3%); P = 1.00] rates were observed between groups A and B.

CONCLUSION

Metformin administration as well as LOD improves the effectiveness of CC for ovulation induction in overweight infertile CC-resistant women with PCOS.

Metformin in polycystic ovary syndrome

PURPOSE OF REVIEW

Metformin has become an established treatment for women with polycystic ovary syndrome, although controversy remains as to how effective it is and in which populations it should be used. This review examines the recent literature in order to ascertain the evidence for the benefits and disadvantages of using metformin in women with polycystic ovary syndrome.

RECENT FINDINGS

A Cochrane systematic review and metaanalysis examined the evidence for metformin in treating polycystic ovary syndrome. Since this was published there have been a number of new trials, some of which have been reasonably large involving participants from many different countries.

SUMMARY

Evidence shows that metformin is effective in inducing ovulation, has some marginal benefit in improving aspects of the metabolic syndrome, improves objective measures of hirsutism, and seems to be effective in both obese and lean individuals. However, it has significant side effects, and the high levels of effectiveness that were reported by some early trials have not been replicated. Metformin should always be used as an adjuvant to general lifestyle improvements, and not as a replacement for increased exercise and improved diet.

Medical treatment regimens of hirsutism

Hirsutism, which is a common clinical problem in women of reproductive age, is characterized by excessive growth of terminal hair in the androgen-sensitive skin regions. It is the result of either androgen excess or increased sensitivity of the hair follicles to normal levels of androgens. The management, which includes cosmetic measures and medical treatment, is far from satisfactory. Anti-androgen drugs play a key role in the treatment of hirsutism, but they have some side-effects which may result in cessation of the drug. On the other hand, anti-androgen treatment often needs to be continued for a long time. So, safe, inexpensive, and effective anti-androgen drugs are needed. Recently low-dose anti-androgen drugs have been shown to be effective in the maintenance of treatment. On the other hand, cyproterone acetate plus ethyniloestradiol and spironolactone, cyproterone acetate plus ethyniloestradiol and finasteride, and spironolactone and finasteride combinations have been used successfully in decreasing the hirsutism score. There are also some promising data regarding the effects of insulin sensitizers in the treatment of hirsutism, particularly in patients with polycystic ovarian syndrome. In the present review, the main features of anti-androgen drugs, new combined treatments, and insulin sensitizers in the treatment of hirsutism are discussed.