Efficacy of hysteroscopy in improving reproductive outcomes of infertile couples: a systematic review and meta-analysis

The scientific community has been re-evaluating the clinical relevance of hysteroscopy in the diagnosis and treatment of uterine factors and its role in the infertility work-up, thanks to its potential capability to improve reproductive outcomes and reduce time to pregnancy. The objective of this systematic review and meta-analysis was to assess the efficacy of diagnostic and operative hysteroscopy in improving the live birth rate (LBR) of infertile women, with and without intrauterine abnormalities, at any stage of the infertility work-up. PubMed, Embase, the Cochrane Library and the Clinical Trials Registry using Medical Subject Headings and free text terms were searched up to June 2014, without language or year restrictions. Randomized controlled trials (RCTs) enrolling infertile women with no suspected intrauterine cavity abnormalities and comparing hysteroscopy versus no hysteroscopy at any stage of the diagnostic work-up, but prior to the first attempt of standard IVF or ICSI or after (one or more) failed attempts of IVF/ICSI were included. RCTs enrolling infertile women with intrauterine abnormalities and comparing operative versus diagnostic hysteroscopy were also included. Risk of bias was assessed using the criteria recommended by the Cochrane Collaboration and the overall quality of evidence was assessed using the GRADE approach. Results were pooled by meta-analysis using the random effect model. The primary outcome evaluated was the LBR, while secondary outcomes were pregnancy rate, miscarriage rate and procedure-related complications. Five hundred and eighty-eight records were retrieved after removing duplicates. Nine studies were included, with 2976 participants. Four studies included infertile women with one or more failed IVF/ICSI cycles. Two studies included infertile women who were candidates for their first IVF/ICSI. One study included candidates both for first IVF/ICSI and with one or more failed IVF/ICSI cycles. Two studies included infertile women affected by uterine fibroids and endometrial polyps, who had not received IVF/ICSI nor were candidates. Seven studies were included in the meta-analysis. Comparing hysteroscopy with no hysteroscopy prior to any (first or subsequent) IVF/ICSI attempt in infertile women without intrauterine abnormalities, there was very low-quality evidence that hysteroscopy increased LBR (relative risk (RR) 1.48, 95% confidence interval (CI) 1.20-1.81; three studies with 1088 participants) and moderate quality evidence that it increased pregnancy rate (RR 1.45, 95% CI 1.26-1.67; seven studies, 2545 participants). Results on pregnancy rate were confirmed in the subgroup analysis of five studies including only women with one or more implantation failures (RR 1.41, 95% CI 1.14-1.75) and three studies where hysteroscopy was performed before the first IVF/ICSI attempt (RR 1.55, 95% CI 1.26-1.91). Comparing operative hysteroscopy for intrauterine abnormalities in infertile women with already diagnosed polyps or fibroids, there was low-quality evidence that operative hysteroscopy increases pregnancy rate (RR 2.13, 95% CI 1.56-2.92). None of the studies comparing operative versus diagnostic hysteroscopy assessed LBR. Robust and high-quality RCTs are still needed before hysteroscopy can be regarded as a first-line procedure in all infertile women, especially during the basal clinical assessment of the couple, when assisted reproductive treatment is not indicated yet.