Abstract: Two studies met the inclusion criteria. 1. Randomised comparison between operative hysteroscopy versus control for unexplained subfertility associated with suspected major uterine cavity abnormalities. In women with otherwise unexplained subfertility and submucous fibroids, we were uncertain whether hysteroscopic myomectomy improved the clinical pregnancy rate compared to expectant management (odds ratio (OR) 2.44, 95% confidence interval (CI) 0.97 to 6.17; P = 0.06, 94 women; very low-quality evidence). We are uncertain whether hysteroscopic myomectomy improves the miscarriage rate compared to expectant management (OR 1.54, 95% CI 0.47 to 5.00; P = 0.47, 94 women; very low-quality evidence). We found no data on live birth or hysteroscopy complication rates. We found no studies in women with endometrial polyps, intrauterine adhesions or uterine septum for this randomised comparison. 2. Randomised comparison between operative hysteroscopy versus control for suspected major uterine cavity abnormalities prior to medically assisted reproduction. The hysteroscopic removal of polyps prior to IUI may have improved the clinical pregnancy rate compared to diagnostic hysteroscopy only: if 28% of women achieved a clinical pregnancy without polyp removal, the evidence suggested that 63% of women (95% CI 45% to 89%) achieved a clinical pregnancy after the hysteroscopic removal of the endometrial polyps (OR 4.41, 95% CI 2.45 to 7.96; P < 0.00001, 204 women; low-quality evidence). We found no data on live birth, hysteroscopy complication or miscarriage rates in women with endometrial polyps prior to IUI. We found no studies in women with submucous fibroids, intrauterine adhesions or uterine septum prior to IUI or in women with all types of suspected uterine cavity abnormalities prior to IVF/ICSI. Uncertainty remains concerning an important benefit with the hysteroscopic removal of submucous fibroids for improving the clinical pregnancy rates in women with otherwise unexplained subfertility. The available low-quality evidence suggests that the hysteroscopic removal of endometrial polyps suspected on ultrasound in women prior to IUI may improve the clinical pregnancy rate compared to simple diagnostic hysteroscopy. More research is needed to measure the effectiveness of the hysteroscopic treatment of suspected major uterine cavity abnormalities in women with unexplained subfertility or prior to IUI, IVF or ICSI.

Plain-language summary: We found two studies. The first study compared the removal of fibroids versus no removal in 94 women wishing to become pregnant spontaneously from January 1998 to April 2005. The second study compared the removal of polyps versus simple hysteroscopy only in 204 women before insemination with husband's sperm from January 2000 to February 2004. The evidence is current to April 2018. Neither study reported funding sources. In women with fibroids wishing to become pregnant spontaneously we were uncertain whether removal of the fibroids improved the pregnancy or miscarriage rate compared to usual management: uncertainty remains because the number of women (94) and the number of pregnancies (30) were too small and the quality of the evidence was very low. We found no data on live birth or complications due to surgery. We found no studies on women with polyps, septa or adhesions. The hysteroscopic removal of polyps prior to intrauterine insemination (IUI; a fertility treatment where sperm is placed inside a woman's womb to fertilise the egg) is may improve the pregnancy rate compared to not removing polyps. If 28% of women become pregnant without surgery, the evidence suggests that about 63% of women will become pregnant following removal of polyps. We found no data on number of live births, hysteroscopy complications or miscarriage rates prior to IUI. We retrieved no studies in women before other fertility treatments. More studies are needed before hysteroscopy can be proposed as a fertility-enhancing procedure in the general population of women having difficulty becoming pregnant. The quality of the evidence retrieved was very low to low due to the limited number of participants and the poor design of the studies.