Human Papillomavirus (HPV) is a highly prevalent virus that infects the skin and mucous membranes, representing the most common sexually transmitted infection worldwide. Most sexually active individuals will contract a strain of HPV at some point, often without knowing it, as the infection typically clears on its own. While the virus is widely known for its potential link to certain cancers, it also raises significant concerns about the possibility of infertility. Understanding the current scientific findings regarding HPV’s effect on the ability to conceive and carry a pregnancy is important. This article addresses the relationship between HPV and reproductive health in both women and men.
HPV and Female Fertility Risk
The presence of the Human Papillomavirus infection itself is not considered a direct cause of primary female infertility. The greater concern for female reproductive health arises indirectly from the treatments required for high-grade cervical changes caused by persistent infection. These changes, known as cervical intraepithelial neoplasia (CIN), are precancerous lesions that require removal to prevent progression to cervical cancer.
Procedures used to treat these lesions, such as the Loop Electrosurgical Excision Procedure (LEEP) or cold knife cone biopsy, involve removing a portion of the cervix. While effective at preventing cancer, the surgical removal of cervical tissue can lead to structural changes. A potential complication is the development of scar tissue that narrows the cervical opening, known as cervical stenosis.
Cervical stenosis may impair fertility by physically blocking sperm from traveling through the cervix into the uterus. Furthermore, removing a significant amount of tissue can compromise the cervix’s structural integrity, potentially leading to cervical insufficiency. This is a weakened cervix that may prematurely shorten or open during pregnancy, raising the risk of preterm delivery or late miscarriage.
Scientific studies find that women who have undergone these procedures are generally not less likely to conceive compared to women who have not. However, the risk of complications like preterm birth is elevated following excisional procedures, particularly if a large section of the cervix was removed. The link between HPV and reproductive challenges in women is primarily mediated by the necessary treatment of precancerous lesions, rather than the virus itself.
HPV and Male Fertility Risk
Research into HPV and male reproductive function suggests a more direct mechanism of potential impact on fertility. The virus has been detected in semen, where it can attach to sperm cells and affect their function. Studies show that the prevalence of HPV DNA in semen is higher in men experiencing unexplained infertility compared to the general population, with estimates ranging from 10% to 35% in some infertile groups.
The binding of HPV virions to the sperm head may interfere with parameters essential for successful fertilization. Seminal HPV infection is linked to a reduction in sperm motility, which is the sperm’s ability to move effectively. Reduced motility hinders the sperm’s journey to the egg, decreasing the likelihood of natural conception.
HPV infection is also associated with an increase in sperm DNA fragmentation, which is damage to the genetic material carried by the sperm. High levels of DNA fragmentation negatively affect fertilization capacity and may be linked to early embryonic developmental issues or recurrent miscarriage in a partner. While the presence of HPV in semen is not a definitive cause of infertility, it is considered a contributing factor in some cases of male factor or unexplained infertility.
HPV’s Role in Pregnancy and Delivery
For an established pregnancy, an active HPV infection poses minimal risk to the developing fetus. The virus is not linked to an increased risk of miscarriage or other major adverse pregnancy outcomes. However, the presence of an active infection, particularly genital warts, can lead to concerns about transmission during delivery.
The risk of vertical transmission, where the virus is passed from mother to infant, is low. Transmission most often occurs during passage through the birth canal, with the infant coming into contact with infected cells. In rare instances, this vertical transmission can lead to the infant developing a serious condition called recurrent respiratory papillomatosis (RRP).
RRP is characterized by the growth of warts in the throat, most commonly on the vocal cords, which can obstruct the airway and require frequent surgical procedures. Standard medical guidelines recommend against performing a Caesarean section solely to prevent HPV transmission, as the risk of RRP is extremely rare. A Caesarean delivery is only considered if large genital warts are present that could obstruct the birth canal or cause excessive bleeding during a vaginal delivery.
Prevention and Monitoring
Proactive steps are available to protect reproductive health and minimize the potential indirect risks associated with HPV infection. Primary prevention involves immunization through available vaccines that protect against the most common high-risk types of the virus. Vaccination is most effective when administered before an individual becomes sexually active. It is recommended for individuals up to age 26, and can be considered through age 45 after a discussion with a healthcare provider.
Secondary prevention focuses on early detection of precancerous changes through routine screening protocols. For individuals with a cervix, this includes cervical cytology, commonly known as a Pap test, and testing for high-risk HPV types. Current guidelines recommend various screening schedules, such as primary HPV testing every five years, or co-testing (HPV test with a Pap test) every five years, depending on age and previous results.
Timely and consistent screening allows for the identification and treatment of high-grade lesions before they progress to cancer. This early intervention is important because it allows for the use of less aggressive treatments, or for treatment to be performed before conception is attempted. Following treatment, continued monitoring is recommended to ensure the abnormal cells do not return.