Insights into the role of cervical mucus and vaginal pH in unexplained infertility

Abstract

Unexplained infertility diagnosis is made in the presence of a normal semen analysis when tubal patency and normal ovulatory function are established. Among several potential causes, unexplained infertility could be attributed to vaginal pH and cervical mucus abnormalities. Although the vaginal canal and the cervix generally function as effective barriers to sperm, and although the production of mucus is essential to transport them from the vagina to the uterine cavity, these factors receive little attention in the investigation of couples with unexplained infertility. A substantial reduction in sperm number occurs as they transverse the cervix. From an average of 200 to 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 natural conception and be a cause of infertility. In this review, we discuss 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.

Assessment of the Microbiome Collected from the Reproductive Tracts of Women from Saudi Arabia and Its Potential Influence on Infertility

“…Indeed, the glycogen is deposited in the epithelial cells of the vagina, which allows the proliferation of lactobacilli and the breakdown of this cellular glycogen. As a result, large amounts of lactic acid (generated by glucose anaerobic fermentation) and hydrogen peroxide are produced to decrease the vaginal pH level to the range of 3.5 -4.5 [14] [15]. The latter provides a natural barrier to infections and prevents the uncontrolled growth of other bacteria present in the vagina.…”

“…Cervical mucus abnormalities can result in infertility (approximately 3% of couples are facing infertility due to cervical mucus problems in females). In fact, alterations in the cervicovaginal mucus can affect its composition, which is generally associated with cervicitis [15] and acute inflammatory conditions. Therefore, the secreted mucus will be of low viscosity but with high leukocyte content.…”

“…Cervical mucus is considered to be a hydrogel that is composed of a highmolecular-weight component (gel phase) and a low-molecular-weight component (cervical plasma) [15]. Cervical mucus abnormalities can result in infertility (approximately 3% of couples are facing infertility due to cervical mucus problems in females).…”

Current State of Microbicide Development

“…50 Different stimuli can be considered in the design of drug delivery systems, such as temperature, pH, light, electric and magnetic fields, or enzymatic. 50 The FGT has a normal pH around 3.8-4.5, 51 which is a property that can be utilized to design drug delivery systems that respond to changes in the acidity of the vaginal area. In fact, during sexual intercourse, the presence of seminal fluid (pH 7-8.5) 51 can increase the pH of the FGT up to around neutral for 6-8 hours.…”

“…50 The FGT has a normal pH around 3.8-4.5, 51 which is a property that can be utilized to design drug delivery systems that respond to changes in the acidity of the vaginal area. In fact, during sexual intercourse, the presence of seminal fluid (pH 7-8.5) 51 can increase the pH of the FGT up to around neutral for 6-8 hours. 52 In a study published by Mahalingam et al, 53 the authors developed a synthetic mucinlike polymer that will crosslink upon increases in pH to impede the movement of free HIV.…”