Efficacy of hysteroscopy in improving fertility outcomes in women undergoing assisted reproductive technique: a systematic review and meta-analysis of randomized controlled trials.

Introduction: Usefulness of hysteroscopy before assisted reproductive technique (ART) was considered debatable. However, over the last decade, several new trials were added to available literature. We aimed to assess the impact of diagnostic and operative hysteroscopy on reproductive outcomes of infertile women with and without intrauterine abnormalities.Materials and methods: MEDLINE, Scopus, Scielo, EMBASE, Cochrane Library at CENTRAL, PROSPERO, CINAHL, grey literature, conference proceedings, and international controlled trials registries were searched without temporal, geographical, or language restrictions. Randomized controlled trials (RCTs) of infertile women comparing hysteroscopy versus no hysteroscopy prior to the first ART or after at least one failed attempt were included. RCTs of infertile women with intrauterine pathology comparing diagnostic vs operative hysteroscopy were included in separate analysis. Random-effect meta-analysis was conducted according to PRISMA guidelines. GRADE and Cochrane criteria were used for quality of evidence and risk of bias assessment. Primary outcome was live birth rate (LBR). Secondary outcomes were clinical pregnancy (CPR) and pregnancy loss rate (PLR).Results: Fifteen studies (5038 women) were included. Compared to no hysteroscopy before first or after failed ART attempts, moderate quality evidence showed that hysteroscopy increased the LBR (relative risk (RR) 1.24, 95% confidence interval (CI) 1.09-1.43, I-2=21%), confirmed by subgroup analysis for women with failure after one or more ART cycles (RR 1.43, 95% CI 1.19- 1.72, I-2=0%) but not before the first ART. Moderate quality evidence showed that it increased the CPR (RR 1.36, 95% CI 1.18-1.57; I-2=51%), confirmed in subgroup analysis for both implantation failure (RR 1.40, 95% CI 1.12-1.74, I-2=52%) and before first ART (RR 1.32, 95% CI 1.11-1.57, I2=42%). Low-quality data suggest that operative hysteroscopy increases CPR when used to treat intrauterine pathologies (RR 2.13, 95% CI 1.56 - 2.92, I-2=0%).Conclusions: Although moderate quality evidence supports performing hysteroscopy before ART in women with history of implantation failure, hysteroscopic evaluation of uterine cavity should be considered a first-line technique in all infertile women undergoing ART. Additional high-quality RCTs are still needed, particularly to assess yield during couple's initial evaluation even before ART is considered.