European Journal of Obstetrics & Gynecology and Reproductive Biology
ReviewGenital tract infections and infertility
Introduction
Infertility can be defined as the lack of a conception after at least one year of constant, unprotected sexual intercourse. The underlying causes may be ascribed to pathologic conditions affecting one or both members of a couple. Male genital affections that may preclude fertility include genital injury, infections of semen, testes and accessory glands, genital tract obstructions, varicocele, genital malformations, endocrine and metabolic diseases, drug use and abuse, and allegedly psychiatric conditions. In female, factors leading to infertility are usually divided into endocrine, vaginal, cervical, uterine, tubal and pelvic-peritoneal. A form of infertility of immune origin has also been identified as a result of the presence of anti-sperm antibodies. A great number of infertility cases still remain unexplained.
Section snippets
Infertility and infections
Many microorganisms seem to be involved in male reproductive failure in various ways, and to different degrees of statistical association. Infections of the lower genital tract seem to have little importance, if not, in the unlikely event of an occlusion. However such infections, as well as those involving other parts of the male genito-urinary tract, may cause a microbial colonization of the semen.
Virtually all parts of the female reproductive system may be influenced by infectious agents;
Genital mycoplasmas
These microorganisms are frequently present in the genital tract and semen of both fertile and infertile men. This is particularly true for Ureaplasma urealyticum, and slightly for both Mycoplasma hominis[1] and Mycoplasma genitalium. It is not clear whether M. hominis and U. urealyticum are to be considered the actual causes of the genital diseases (urethritis, prostatitis, rarely orchitis) with which they are associated [2]. However, results of human and animal inoculation studies support the
Yeasts
Candida albicans commonly colonizes the urethra, but rarely the accessory glands. It can be found in the semen and may compromise in vitro fertilization: C. albicans, as well as its filtrates, have an inhibitory effect on human sperm motility, and impaired the ultrastructure of human spermatozoa, which could be associated with male infertility [33].
C. albicans is a common commensal of the female genital tract and may occasionally cause diseases ranging from mild forms of vaginitis and
Parasites, tropical infections and rare conditions
Trichomonas vaginalis has a worldwide distribution and is a common parasite of the male genital tract. The organism can, in rare cases, cause a non-gonococcal urethritis, and perhaps prostatitis and other genital tract disorders. Proteinases released by T. vaginalis can also inhibit sperm motility in vitro, even after the microorganism has been removed from the culture medium [35]. T. vaginalis is a common vaginal parasite with worldwide distribution, but it is more common amongst women and
Herpesvirus (HSV)
The presence of HSV DNA in human spermatozoa has been proven [43], also if in low percentage, and this event was significantly related to poor sperm count and reduced motility [44]. Antiviral treatment of male infertility patients positive for HSV in semen resulted in successful pregnancies. Thus, HSV infection of the male genital tract could explain some cases of male infertility, as a consequence of its association with decreased semen quality [45]. A significant association seems to exist
A few words on diagnosis and treatment of genital infections
A discussion of the microbiological diagnosis of the described diseases, summarized in Table 1, is beyond the scope of this review; reader can go to Murray et al. [50] for detailed informations. Anyhow, a brief presentation of proposed therapeutic approaches of some important genital pathogens, is provided in Table 2.
Final considerations
Infections, definitely, represent a menace for human fertility and, despite the fact that the HIV-AIDS pandemic raised attention towards sexually transmitted infections (STIs), a report by the World Health Organization (“Global prevalence and incidence of selected curable sexually transmitted infections. Overview and estimates”. WHO/HIV_AIDS/2001.02, Table 3) confirms that STIs seem still to be in a phase of rapid worldwide expansion.
STIs may be present without symptoms or with symptoms that
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