Cervical hostility and vaginal pH in Females with unexplained infertility

Abstract

A substantial diminution in sperm number occurs as they transverse the cervix. From an average of 200-300 million sperm deposited in the vagina, only a few hundred achieve proximity to the oocyte. Given this expected high spermatozoa loss, a slight modification in cervical mucus may rapidly transform the cervix into a "hostile" environment, which, together with changes in vaginal environment and cervix structure, may prevent spontaneous conception and be a cause of infertility. The cervix generally functions as an effective barrier to sperm and the production of mucus is essential to transport them from the vagina to the uterine cavity. In this chapter, we explain the physiological role of the vaginal pH and cervical mucus in fertility, and describe several conditions that can render the cervical mucus hostile to sperm and, therefore, be implicated in the pathophysiology of unexplained infertility.