Assisted reproductive technologies and uterine factors influencing their success.

Congenital and acquired uterine factors are known to influence the success of assisted reproductive technologies (ARTs). Several studies analyzed the role of uterine septa, adenomyosis, myomas, endometrial polyps and intrauterine adhesions in female infertility. All of them might cause defective endometrial receptivity and consequently decreased embryo implantation and pregnancy rate. In particular, septate uterus represents the most frequent Müllerian anomaly leading to an increased risk of abortion. Many studies evaluated the role of hysteroscopic metroplasty on fertility outcomes, but this topic remains controversial. The role of adenomyosis in infertility is still debated and, even if different mechanisms have been described to explain implantation failure, there are still conflicting findings on the impact of adenomyosis on ART. The effects of myomas on fertility mainly depend on their type, so that submucous have a detrimental impact on fertility, subserous seem to have no effect, while there is no clear consensus regarding the effect of intramural. Consequently, the potential influence of myomectomy on fertility outcomes depends on the type, being mandatory only the hysteroscopic treatment of submucous myomas. The effect of endometrial polyps on endometrial receptivity and fertility is not clear, even if some studies identified improvement in pregnancy rates after hysteroscopic polipectomy. In presence of intrauterine adhesions, infertility represents the most common manifestation and the restoring of normal uterine cavity should be always pursued when possible.