The adjuvant effect of metformin and N-acetylcysteine to clomiphene citrate in induction of ovulation in patients with Polycystic Ovary Syndrome

Efficacy of N-Acetylcysteine in Polycystic Ovary Syndrome: Systematic Review and Meta-Analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age and requires better treatment. N-acetylcysteine (NAC) is known to be beneficial under such conditions owing to its antioxidant potential and insulin-sensitizing properties. The effect of NAC on the reproductive outcomes of PCOS patients was examined in this meta-analysis.

METHODS

In accordance with PRISMA standards, this meta-analysis included studies that compared N-acetylcysteine, metformin, clomiphene citrate, and a placebo in patients with POCS. The main indicators were follicular growth, endometrial thickness, and hormone level. The risk of bias was evaluated using the Cochrane ROB2 tool.

RESULTS

Twenty-two studies (n = 2515) were included. NAC was associated with a statistically significant increase in progesterone (SMD 0.95, 95% CI: 0.13-1.77, p = 0.02) and endometrial thickness (SMD 0.58, 95% CI: 0.10-1.06, p = 0.02) compared to the placebo and other drugs (SMD 0.71, 95% CI: 0.48-0.94, p < 0.0001). LH levels were significantly increased by NAC compared to metformin (SMD 0.67, 95% CI: 0.23-1.12, p = 0.003). However, no significant differences were observed in the estradiol, SHBG, or FSH levels.

CONCLUSIONS

NAC had a major effect on progesterone, endometrial thickness, and LH levels in women with PCOS. Therefore, it may be a potential treatment option.

Jujuboside A Attenuates Polycystic Ovary Syndrome Based on Estrogen Metabolism Through Activating AhR-mediated CYP1A2 Expression

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. This study aimed to investigate the therapeutic effects and mechanism of Jujuboside A on PCOS using a dehydroepiandrosterone (DHEA)-induced PCOS mouse model. Estrogen and androgen homeostasis was evaluated in serum from both clinical samples and PCOS mice. The stages of the estrous cycle were determined based on vaginal cytology. The ovarian morphology was observed by stained with hematoxylin and eosin. Moreover, we analyzed protein expression of cytochrome P450 1A1 (CYP1A1), cytochrome P450 1A2 (CYP1A2) and aryl hydrocarbon receptor (AhR) in ovary and KGN cells. Molecular docking, immunofluorescence, and luciferase assay were performed to confirm the activation of AhR by Jujuboside A. Jujuboside A effectively alleviated the disturbance of estrogen homeostasis and restored ovarian function, leading to an improvement in the occurrence and progression of PCOS. Furthermore, the protective effect of JuA against PCOS was dependent on increased CYP1A2 levels regulated by AhR. Our findings suggest that Jujuboside A improves estrogen disorders and may be a potential therapeutic agent for the treatment of PCOS.

The effects of N-acetylcysteine on ovulation and sex hormones profile in women with polycystic ovary syndrome: a systematic review and meta-analysis

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases characterised by unusual levels of sex hormones and dysfunction of the ovaries. The infertility rate is high among patients with PCOS. Unusual hormonal status can lead to the inability of ovaries to release functional and mature follicles. Clinical trials on the effects of N-acetylcysteine (NAC) supplementation on ovulation and sex hormones profile in women with PCOS have been controversial. We performed a systematic review and meta-analysis to evaluate the potential effects of NAC supplementation on ovulation and sex hormones profile. PubMed, Scopus, Embase, Web of Science and Cochrane Central library international databases were searched till September 2021. Meta-analysis was performed using a random-effects approach in case of significant between-study heterogeneity. Eighteen studies, including 2185 participants, were included in the present meta-analysis. NAC significantly reduced total testosterone (TT) levels (standardised mean difference (SMD): −0·25 ng/ml; 95 % CI (−0·39, −0·10); ‘P < 0·001’, I2 = 53·9 %, P = 0·034) and increased follicle-stimulating hormone (FSH) levels (SMD: 0·39 mg/ml; 95 % CI (0·07, 0·71); P = 0·01, I2 = 70·9 %, P = 0·002). Oestrogen levels also increased after correcting publication bias. However, no significant effect was observed on the number of follicles, endometrial thickness, progesterone, serum luteinising hormone levels and sex hormone-binding globulin. The results indicated that NAC supplementation decreased TT levels and increased FSH levels. Overall, NAC supplementation might be effective in the improvement of reproductive system function in patients with PCOS.

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.

Effects of N-acetylcysteine and metformin treatment on the stereopathological characteristics of uterus and ovary

In this study, the stereo-pathological effect of metformin and N-acetyl cysteine is evaluated on the uterus and ovary of polycystic ovary syndrome (PCOS) mice. 96 mature females (8-weekold, weight of 20–30 gr) BALB/c mice were classified into 6 groups including the control group (n= 16), letrozole-induced PCOS group (n=16), PCOS + metformin (n=16), PCOS+NAC (n=16) and a separate control group for NAC (n=16). Another PCOS group was maintained for a month to make sure that features remain till the end of the study. Testosterone level, vaginal cytology and stereological evaluations were assessed. Vaginal cytology in letrozole-receiving mice showed a diestrus phase continuity. Testosterone level, body weight, uterine weight, endometrial volume, myometrial volume, gland volume, stromal volume, epithelial volume, vessel volume, daughter and conglomerate glands, endometrial thickness, and myometrial thickness exhibited an increasing trend in the uterus of PCOS mice. While normal gland and vessel length decreased in the PCOS group. Ovarian volume, corticomedullary volume, primary follicles, secondary follicles, and ovarian cysts were increased in PCOS ovaries. While corpus luteum, primordial, graafian, and atretic follicles showed a decline in the PCOS group. NAC and metformin, however, managed to restore the condition to normal. Given the prevalence of PCOS and its impact on fertility, the use of noninvasive methods is of crucial significance. NAC can control and treat pathological parameters and help as a harmless drug in the treatment of women with PCOS.

Oxidative Stress in Polycystic Ovarian Syndrome and the Effect of Antioxidant N-Acetylcysteine on Ovulation and Pregnancy Rate

Polycystic ovarian syndrome (PCOS) is an endocrinological condition that leads to infertility in many females. N-acetylcysteine (NAC), a novel antioxidant, is being used as an adjuvant to treat infertility in females suffering from PCOS. This review aims to evaluate oxidative stress in females suffering from PCOS and assess whether the anti-oxidizing properties of NAC are beneficial in enhancing the rate of ovulation and pregnancy in infertile PCOS females. A literature search was conducted manually on PubMed and Google Scholar databases using the following keywords: “N-Acetylcysteine,” “PCOS,” “Oxidative stress,” “Antioxidants,” and “infertility” alone and/or in combination for data collection. The studies were manually screened and, after applying inclusion-exclusion criteria, 32 studies consisting of 2466 females of the reproductive age group are included in this review. Our review revealed that females suffering from PCOS tend to show elevated levels of inflammatory markers and a decrease in antioxidant capacity. When used in combination with clomiphene citrate or letrozole, NAC increases ovulation and pregnancy rate in infertile females suffering from PCOS and positively affects the quality of oocytes and number of follicles ≥18mm. Moreover, its side effect profile is low. It also results in a mild increase in endometrial thickness in some females. Future studies on a large sample size using NAC alone are highly recommended to evaluate its role as a single-drug therapy for treating infertility in females suffering from PCOS. 

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.

A systematic review of N-acetylcysteine for treatment of acne vulgaris and acne-related associations and consequences: Focus on clinical studies

Acne vulgaris is one of the most common dermatologic disorders affects people of all races and ethnicities and has many adverse effects on the quality of life. The increased bacterial resistance to antibiotics has reduced the effectiveness of treatment with these agents. There is an increasing focus on the involvement of oxidative stress in the pathophysiology of acne. This study investigates the effect of N-acetylcysteine (NAC) as an antioxidant in the treatment of acne vulgaris. This systematic review was conducted through a search in databases such as Science Direct, PubMed, Scielo, and Medline using keywords including acne vulgaris, anti and NAC, and all the keywords associated with each of the subtitles. The factors affecting the occurrence and expansion of acne include increased sebum synthesis, hyperkeratinization of pilosebaceous units, colonization with Propionibacterium acnes, and increased release of inflammatory mediators and ROS. Studies have shown that glutathione stimulation following the administration of NAC increases glutathione levels for the detoxification of oxygen-free radicals. Moreover, NAC prevents the synthesis and release of inflammatory cytokines such as TNF-α, IL-8, IL-6, MP9, and IL-1β and has shown antibacterial activities against important bacteria including E. coli, S. epidermidis, Pseudomonas, and Klebsiella. This medication has anti-proliferative effects and is also used for excoriation and PCOD. The results of the present study showed the beneficial effects of using NAC in patients with acne vulgaris in terms of the disease complications and comorbidities. Given its diverse functional mechanisms, this medication can be used to treat acne and its consequences.

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.

N-acetyl-cysteine as adjuvant therapy in female infertility: a systematic review and meta-analysis

OBJECTIVES

The objective of this study is to explore the efficacy and safety of N-acetyl-cysteine (NAC) as adjuvant therapy in female infertility.

CONTENT

We performed a systematic literature search of PubMed, Cochrane Library, Embase, and Ovid databases through April 2019 for Randomized Controlled Trials (RCTs) evaluating the effectiveness and safety of NAC as adjuvant therapy in female infertility. The outcomes assessed were rates of ovulation, pregnancy, miscarriage and multiple pregnancy, presented as pooled odds ratio with 95% confidence interval (CI) using the random-effects model. Heterogeneity and inconsistency of the measurements were identified through Cochrane's Q statistic and I2 statistic. We also performed a sensitivity analysis, publication bias (using funnel plot and Begg's test), and subgroup analysis.

SUMMARY

Fifteen RCTs recruiting 2330 female receiving NAC were included. The pooled estimate showed the statistically insignificant improvement in outcomes; clinical pregnancy rate 1.55 (95% CI 0.98-2.47; I2=68%; p<0.01), ovulation rate 1.77 (95% CI 0.76-4.14; I2=90%; p<0.01), multiple pregnancy rate 0.83 (95% CI 0.34-1.99; I2=10%; p=0.31) and miscarriage rate 0.76 (95% CI= 0.37, 1.53; I2=0%; p=0.69) . NAC was found less efficacious and safe than metformin in all outcomes. Overall, NAC showed statistically insignificant (OR=0.98-2.47).

OUTLOOK

NAC can be an effective adjuvant in PCOS related and unexplained female infertility. The effect could be more profound in women with high BMI, insulin resistance, and oxidative stress. However, the findings need further confirmation in well-designed randomized controlled trials to examine clinical outcomes such as live birth rate in more extended follow-up periods.

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.

Antioxidants for female subfertility

EDITORIAL NOTE

M.G. Showell, R. Mackenzie‐Proctor, V. Jordan, and R.J. Hart, “Antioxidants for Female Subfertility,” Cochrane Database of Systematic Reviews, no. 8 (2020): CD007807, https://doi.org/10.1002/14651858.CD007807.pub4 This Editorial Note is for the above article, published online on August 27, 2020, in Cochrane Library (cochranelibrary.com), and has been issued by the Publisher, John Wiley & Sons Ltd, in agreement with Cochrane. The Editorial note has been agreed due to concerns discovered by the Cochrane managing editor regarding the retraction of six studies in the Review (Badawy et al. 2006, 10.1016/j.fertnstert.2006.02.097; El Refaeey et al. 2014, 10.1016/j.rbmo.2014.03.011; El Sharkwy & Abd El Aziz 2019a, https://doi.org/10.1002/ijgo.12902; Gerli et al. 2007, https://doi.org/10.26355/eurrev_202309_33752, full text: https://europepmc.org/article/MED/18074942; Ismail et al. 2014, http://dx.doi.org/10.1016/j.ejogrb.2014.06.008; Hashemi et al. 2017, https://doi.org/10.1080/14767058.2017.1372413). In addition, expressions of concern have been published for two studies (Jamilian et al. 2018, https://doi.org/10.1007/s12011-017-1236-3; Zadeh Modarres 2018, https://doi.org/10.1007/s12011-017-1148-2). The retracted studies will be moved to the Excluded Studies table, and their impact on the review findings will be investigated and acted on accordingly in a future update. Initial checks indicate that removal of the six retracted studies did not make an appreciable difference to the results. Likewise, the studies for which Expressions of Concern were issued will be moved to the Awaiting classification table; they did not report any review outcomes, so removal will have no impact on the review findings.

BACKGROUND

A couple may be considered to have fertility problems if they have been trying to conceive for over a year with no success. This may affect up to a quarter of all couples planning a child. It is estimated that for 40% to 50% of couples, subfertility may result from factors affecting women. Antioxidants are thought to reduce the oxidative stress brought on by these conditions. Currently, limited evidence suggests that antioxidants improve fertility, and trials have explored this area with varied results. This review assesses the evidence for the effectiveness of different antioxidants in female subfertility.

OBJECTIVES

To determine whether supplementary oral antioxidants compared with placebo, no treatment/standard treatment or another antioxidant improve fertility outcomes for subfertile women.

SEARCH METHODS

We searched the following databases (from their inception to September 2019), with no language or date restriction: Cochrane Gynaecology and Fertility Group (CGFG) specialised register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL and AMED. We checked reference lists of relevant studies and searched the trial registers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any type, dose or combination of oral antioxidant supplement with placebo, no treatment or treatment with another antioxidant, among women attending a reproductive clinic. We excluded trials comparing antioxidants with fertility drugs alone and trials that only included fertile women attending a fertility clinic because of male partner infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary review outcome was live birth; secondary outcomes included clinical pregnancy rates and adverse events.

MAIN RESULTS

We included 63 trials involving 7760 women. Investigators compared oral antioxidants, including: combinations of antioxidants, N-acetylcysteine, melatonin, L-arginine, myo-inositol, carnitine, selenium, vitamin E, vitamin B complex, vitamin C, vitamin D+calcium, CoQ10, and omega-3-polyunsaturated fatty acids versus placebo, no treatment/standard treatment or another antioxidant. Only 27 of the 63 included trials reported funding sources. Due to the very low-quality of the evidence we are uncertain whether antioxidants improve live birth rate compared with placebo or no treatment/standard treatment (odds ratio (OR) 1.81, 95% confidence interval (CI) 1.36 to 2.43; P < 0.001, I2 = 29%; 13 RCTs, 1227 women). This suggests that among subfertile women with an expected live birth rate of 19%, the rate among women using antioxidants would be between 24% and 36%. Low-quality evidence suggests that antioxidants may improve clinical pregnancy rate compared with placebo or no treatment/standard treatment (OR 1.65, 95% CI 1.43 to 1.89; P < 0.001, I2 = 63%; 35 RCTs, 5165 women). This suggests that among subfertile women with an expected clinical pregnancy rate of 19%, the rate among women using antioxidants would be between 25% and 30%. Heterogeneity was moderately high. Overall 28 trials reported on various adverse events in the meta-analysis. The evidence suggests that the use of antioxidants makes no difference between the groups in rates of miscarriage (OR 1.13, 95% CI 0.82 to 1.55; P = 0.46, I2 = 0%; 24 RCTs, 3229 women; low-quality evidence). There was also no evidence of a difference between the groups in rates of multiple pregnancy (OR 1.00, 95% CI 0.63 to 1.56; P = 0.99, I2 = 0%; 9 RCTs, 1886 women; low-quality evidence). There was also no evidence of a difference between the groups in rates of gastrointestinal disturbances (OR 1.55, 95% CI 0.47 to 5.10; P = 0.47, I2 = 0%; 3 RCTs, 343 women; low-quality evidence). Low-quality evidence showed that there was also no difference between the groups in rates of ectopic pregnancy (OR 1.40, 95% CI 0.27 to 7.20; P = 0.69, I2 = 0%; 4 RCTs, 404 women). In the antioxidant versus antioxidant comparison, low-quality evidence shows no difference in a lower dose of melatonin being associated with an increased live-birth rate compared with higher-dose melatonin (OR 0.94, 95% CI 0.41 to 2.15; P = 0.89, I2 = 0%; 2 RCTs, 140 women). This suggests that among subfertile women with an expected live-birth rate of 24%, the rate among women using a lower dose of melatonin compared to a higher dose would be between 12% and 40%. Similarly with clinical pregnancy, there was no evidence of a difference between the groups in rates between a lower and a higher dose of melatonin (OR 0.94, 95% CI 0.41 to 2.15; P = 0.89, I2 = 0%; 2 RCTs, 140 women). Three trials reported on miscarriage in the antioxidant versus antioxidant comparison (two used doses of melatonin and one compared N-acetylcysteine versus L-carnitine). There were no miscarriages in either melatonin trial. Multiple pregnancy and gastrointestinal disturbances were not reported, and ectopic pregnancy was reported by only one trial, with no events. The study comparing N-acetylcysteine with L-carnitine did not report live birth rate. Very low-quality evidence shows no evidence of a difference in clinical pregnancy (OR 0.81, 95% CI 0.33 to 2.00; 1 RCT, 164 women; low-quality evidence). Low quality evidence shows no difference in miscarriage (OR 1.54, 95% CI 0.42 to 5.67; 1 RCT, 164 women; low-quality evidence). The study did not report multiple pregnancy, gastrointestinal disturbances or ectopic pregnancy. The overall quality of evidence was limited by serious risk of bias associated with poor reporting of methods, imprecision and inconsistency.

AUTHORS' CONCLUSIONS

In this review, there was low- to very low-quality evidence to show that taking an antioxidant may benefit subfertile women. Overall, there is no evidence of increased risk of miscarriage, multiple births, gastrointestinal effects or ectopic pregnancies, but evidence was of very low quality. At this time, there is limited evidence in support of supplemental oral antioxidants for subfertile women.

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.

Comparison of the efficacy between NAC and metformin in treating PCOS patients: a meta-analysis

Our aim is to evaluate the clinical effectiveness and safety by comparing N-acetyl-cysteine (NAC) with metformin administrated by polycystic ovary syndrome (PCOS) patients. Systematic review and meta-analysis of randomized clinical trials (RCTs). MEDLINE, EMBASE, Web of Science and China National Knowledge Infrastructure were searched for studies. 10 studies were considered eligible for inclusion. NAC significantly reduced BMI and total testosterone, there was no significant difference in pregnancy rate, serum LH level, fasting insulin, and LH/FSH ratio. In conclusions, NAC may be considered as an alternative supplement to metformin, but large-scale randomized controlled trials are needed to assess the efficacy and safety of NAC in PCOS patients.

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.

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.

Antioxidants and Oxidative Stress: Focus in Obese Pregnancies

The prevalence of obesity in women of childbearing age around the globe has dramatically increased in the last decades. Obesity is characterized by a low-state chronic inflammation, metabolism impairment and oxidative stress, among other pathological changes. Getting pregnant in this situation involves that gestation will occur in an unhealthy environment, that can potentially jeopardize both maternal and fetal health. In this review, we analyze the role of maternal obesity-induced oxidative stress as a risk factor to develop adverse outcomes during gestation, including reduced fertility, spontaneous abortion, teratogenesis, preeclampsia, and intrauterine growth restriction. Evidences of macromolecule oxidation increase in reactive oxygen species generation and antioxidant defense alterations are commonly described in maternal and fetal tissues. Thus, antioxidant supplementation become an interesting prophylactic and therapeutic tool, that yields positive results in cellular, and animal models. However, the results from most meta-analysis studying the effect of these therapies in complicated gestations in humans are not really encouraging. It is still to be analyzed whether these therapies could work if applied to cohorts of patients at a high risk, such as those with low concentration of antioxidants or obese pregnant women.

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.

Antioxidants for female subfertility

BACKGROUND

A couple may be considered to have fertility problems if they have been trying to conceive for over a year with no success. This may affect up to a quarter of all couples planning a child. It is estimated that for 40% to 50% of couples, subfertility may result from factors affecting women. Antioxidants are thought to reduce the oxidative stress brought on by these conditions. Currently, limited evidence suggests that antioxidants improve fertility, and trials have explored this area with varied results. This review assesses the evidence for the effectiveness of different antioxidants in female subfertility.

OBJECTIVES

To determine whether supplementary oral antioxidants compared with placebo, no treatment/standard treatment or another antioxidant improve fertility outcomes for subfertile women.

SEARCH METHODS

We searched the following databases (from their inception to September 2016) with no language or date restriction: Cochrane Gynaecology and Fertility Group (CGFG) specialised register, the Cochrane Central Register of Studies (CENTRAL CRSO), MEDLINE, Embase, PsycINFO, CINAHL and AMED. We checked reference lists of appropriate studies and searched for ongoing trials in the clinical trials registers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any type, dose or combination of oral antioxidant supplement with placebo, no treatment or treatment with another antioxidant, among women attending a reproductive clinic. We excluded trials comparing antioxidants with fertility drugs alone and trials that only included fertile women attending a fertility clinic because of male partner infertility.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible studies, extracted the data and assessed the risk of bias of the included studies. The primary review outcome was live birth; secondary outcomes included clinical pregnancy rates and adverse events. We pooled studies using a fixed-effect model, and calculated odds ratios (ORs) with 95% confidence intervals (CIs) for the dichotomous outcomes of live birth, clinical pregnancy and adverse events. We assessed the overall quality of the evidence by applying GRADE criteria.

MAIN RESULTS

We included 50 trials involving 6510 women. Investigators compared oral antioxidants, including combinations of antioxidants, N-acetyl-cysteine, melatonin, L-arginine, myo-inositol, D-chiro-inositol, carnitine, selenium, vitamin E, vitamin B complex, vitamin C, vitamin D+calcium, CoQ10, pentoxifylline and omega-3-polyunsaturated fatty acids versus placebo, no treatment/standard treatment or another antioxidant.Very low-quality evidence suggests that antioxidants may be associated with an increased live birth rate compared with placebo or no treatment/standard treatment (OR 2.13, 95% CI 1.45 to 3.12, P > 0.001, 8 RCTs, 651 women, I2 = 47%). This suggests that among subfertile women with an expected live birth rate of 20%, the rate among women using antioxidants would be between 26% and 43%.Very low-quality evidence suggests that antioxidants may be associated with an increased clinical pregnancy rate compared with placebo or no treatment/standard treatment (OR 1.52, 95% CI 1.31 to 1.76, P < 0.001, 26 RCTs, 4271 women, I2 = 66%). This suggests that among subfertile women with an expected clinical pregnancy rate of 22%, the rate among women using antioxidants would be between 27% and 33%. Heterogeneity was moderately high.There was insufficient evidence to determine whether there was a difference between the groups in rates of miscarriage (OR 0.79, 95% CI 0.58 to 1.08, P = 0.14, 18 RCTs, 2834 women, I2 = 23%, very low quality evidence). This suggests that, among subfertile women with an expected miscarriage rate of 7%, use of antioxidants would be expected to result in a miscarriage rate of between 4% and 7%. There was also insufficient evidence to determine whether there was a difference between the groups in rates of multiple pregnancy (OR 1.00, 95% CI 0.73 to 1.38, P = 0.98, 8 RCTs, 2163 women, I2 = 4%, very low quality evidence). This suggests that among subfertile women with an expected multiple pregnancy rate of 8%, use of antioxidants would be expected to result in a multiple pregnancy rate between 6% and 11%. Likewise, there was insufficient evidence to determine whether there was a difference between the groups in rates of gastrointestinal disturbances (OR 1.55, 95% CI 0.47 to 5.10, P = 0.47, 3 RCTs, 343 women, I2 = 0%, very low quality evidence). This suggests that among subfertile women with an expected gastrointestinal disturbance rate of 2%, use of antioxidants would be expected to result in a rate between 1% and 11%. Overall adverse events were reported by 35 trials in the meta-analysis, but there was insufficient evidence to draw any conclusions.Only one trial reported on live birth, clinical pregnancy or adverse effects in the antioxidant versus antioxidant comparison, and no conclusions could be drawn.Very low-quality evidence suggests that pentoxifylline may be associated with an increased clinical pregnancy rate compared with placebo or no treatment (OR 2.07, 95% CI 1.20 to 3.56, P = 0.009, 3 RCTs, 276 women, I2 = 0%). This suggests that among subfertile women with an expected clinical pregnancy rate of 25%, the rate among women using pentoxifylline would be between 28% and 53%.There was insufficient evidence to determine whether there was a difference between the groups in rates of miscarriage (OR 1.34, 95% CI 0.46 to 3.90, P = 0.58, 3 RCTs, 276 women, I2 = 0%) or multiple pregnancy (OR 0.78, 95% CI 0.20 to 3.09, one RCT, 112 women, very low quality evidence). This suggests that among subfertile women with an expected miscarriage rate of 4%, the rate among women using pentoxifylline would be between 2% and 15%. For multiple pregnancy, the data suggest that among subfertile women with an expected multiple pregnancy rate of 9%, the rate among women using pentoxifylline would be between 2% and 23%.The overall quality of evidence was limited by serious risk of bias associated with poor reporting of methods, imprecision and inconsistency.

AUTHORS' CONCLUSIONS

In this review, there was very low-quality evidence to show that taking an antioxidant may provide benefit for subfertile women, but insufficient evidence to draw any conclusions about adverse events. At this time, there is limited evidence in support of supplemental oral antioxidants for subfertile women.

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.