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Introduction High levels of anti-Mullerian hormone and a high antral follicle count in women with polycystic ovary syndrome, reflecting increased ovarian antral follicles, predisposes them to have a high number of retrieved oocytes with in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and an increased risk of ovarian hyperstimulation syndrome. Inositols, which act as insulin sensitizers, have the potential to alter folliculogenesis and the functional ovarian reserve, with subsequent benefits to reproductive outcomes following IVF/ICSI treatment. Published literature is, however, unable to provide definitive evidence of its efficacy. The objective of our review was to evaluate the effect of inositols on anti-Mullerian hormone, antral follicle count and reproductive outcomes in women with polycystic ovary syndrome undergoing IVF/ICSI. Material and methods We performed a literature search using standard methodology recommended by Cochrane. Randomized controlled trials and non-randomized studies comparing inositols with no treatment, placebo or other treatment were included in the review. Using standard methodology recommended by Cochrane we pooled results using the random effects model; our findings were reported as relative risk or mean differences. PROSPERO registration: CRD42017082275. Results We included 18 trials. The primary outcome was a change in anti-Mullerian hormone and antral follicle count before and after treatment, for which data were unsuitable for meta-analysis. A narrative review showed no consistent direction or size of effect. A meta-analysis for the secondary outcomes showed no evidence of a significant difference between inositol and control groups for any outcome: number of oocytes (mean difference -0.39, 95% confidence interval [CI] -1.11 to 0.33), number of metaphase II oocytes (mean difference 0.29, 95% CI -0.83 to 1.40), number of top grade embryos (risk ratio [RR] 1.02, 95% CI 0.93-1.12), clinical pregnancy rate (RR 1.16, 95% CI 0.87-1.53), and risk of ovarian hyperstimulation syndrome (RR 0.73, 95% CI 0.39-1.37). The quality of evidence was assessed as very low. Conclusions There is insufficient evidence for an effect of inositols on ovarian reserve markers and to support their use as pretreatment before IVF/ICSI in women with polycystic ovary syndrome.

Polycystic ovary syndrome is a common cause of anovulation and infertility, and a risk factor for development of metabolic syndrome and endometrial cancer. Systematic review and meta-analysis of randomised controlled trials (RCT) that evaluated the effects of inositol as an ovulation induction agent. We searched MEDLINE, EMBASE, Cochrane and ISI conference proceedings, Register and Meta-register for RCT and WHO trials’ search portal. We included studies that compared inositol with placebo or other ovulation induction agents. Quality of studies was assessed for risk of bias. Results were pooled using random effects meta-analysis and findings were reported as relative risk or standardised mean differences. We included ten randomised trials. A total of 362 women were on inositol (257 on myo-inositol; 105 on di-chiro-inositol), 179 were on placebo and 60 were on metformin. Inositol was associated with significantly improved ovulation rate (RR 2.3; 95% CI 1.1–4.7; I2 = 75%) and increased frequency of menstrual cycles (RR 6.8; 95% CI 2.8–16.6; I2 = 0%) compared with placebo. One study reported on clinical pregnancy rate with inositol compared with placebo (RR 3.3; 95% CI 0.4–27.1), and one study compared with metformin (RR 1.5; 95% CI 0.7–3.1). No studies evaluated live birth and miscarriage rates. Inositol appears to regulate menstrual cycles, improve ovulation and induce metabolic changes in polycystic ovary syndrome; however, evidence is lacking for pregnancy, miscarriage or live birth. A further, well-designed multicentre trial to address this issue to provide robust evidence of benefit is warranted. Tweetable abstract Inositols improve menstrual cycles, ovulation and metabolic changes in polycystic ovary syndrome