Human papillomavirus (HPV)
Human papillomavirus, or HPV, is the most prevalent sexually transmitted disease among sexually active individuals. At some point in their lives, 75% of women and 85% of men are infected with the virus. In 90% of cases, human papillomavirus infections tend to clear up by themselves. However, they can develop into lesions such as cervical cancer. In this article, Dr Sofía Olalla, a gynaecologist at Instituto Bernabeu in Madrid, tells us all about HPV and how it can affect fertility in men and women.
What is human papillomavirus?
The words behind the acronym HPV are human papillomavirus, a DNA virus that causes the most common sexually transmitted infection in humans. In fact, at some point in their lives, 75% of sexually-active women and 85% of sexually-active men are infected with the virus.
Out of the 150 different isolated types of HPV, at least 40 of them are transmitted through sexual contact, infecting the skin and mucous around the anogenital area, mouth and upper respiratory tract in men and women.
Human papillomavirus is usually inoffensive and disappears of its own accord. Around 90% of infections are transitory and get cleared up by our immune system. However, certain factors can favour persistence of the infection and lead to premalignant or malignant lesions associated with the virus. Since it is an oncogenic virus, it can sometimes turn into lesions such as cervical cancer. The oncogenic capacity of the virus is classified into high and low-risk groups.
In addition to infection by a high-risk virus, the following factors can affect persistence of the virus: a weakened immune system, smoking, prolonged use of oral contraceptives and coinfection with other sexually transmitted microorganisms, such as chlamydia or genital herpes.
I have received a positive HPV test result: could this affect my fertility or pregnancy?
When couples who are trying for a baby test positive for HPV, the first question they tend to ask themselves is if the infection could affect their fertility or pregnancy. Several studies have attempted to answer this question but, so far, much of the available data is disputed.
Studies have shown that the virus is present in semen samples and has been detected in approximately 16% of infertile men and 10% of the general population. There is also increased prevalence of the high-risk virus; subtype 16 is the most oncogenic and common.
Several studies have associated this with male subfertility and particularly with abnormalities in semen. It has been demonstrated that it decreases sperm mobility and increases sperm DNA fragmentation.
How does HPV affect fertility in women?
For the time being, we know less about the potential impact of the virus on female fertility, pregnancies and success rates during assisted reproduction treatment.
While some studies have linked high-risk HPV infections to female infertility rates, recent research has not been able to demonstrate the association.
It is believed that a positive virus test result could be an infertility risk factor, but not a cause in itself. One of the reasons is that, since it is a sexually transmitted disease, the infection may be present alongside other pathogens such as chlamydia, which can obstruct the Fallopian tubes.
Lesions in the cervix caused by the virus could also be a contributing factor in infertility since they affect how spermatozoa travel through the cervix.
Some studies also indicate that it could lead to increased complications during pregnancy, such as pregnancy loss or premature childbirth.
The impact that the infection has on the results of assisted reproduction treatment is unclear. Some authors have observed a greater risk of unsuccessful treatment, while others have not. Studies on animals suggest that the virus could decrease embryo survival rates and the chances of pregnancy, and increase the risk of pregnancy loss. Studies to determine if this is the case in humans would need to be carried out.
How can I protect myself from infection?
Prevention is the best way of avoiding any negative impact on fertility and, in particular, cancer. Thankfully, nowadays we have some very efficient tools at our disposal.
- The HPV vaccine, which is administered to all girls in Spain as a means of protecting the general population. Some autonomous communities also now administer it to boys.
- Use of barrier contraceptives, such as condoms, during sexual intercourse.
- A healthy lifestyle and refraining from smoking as a means of maintaining a strong immune system that can withstand infection.
Dr Sofía Olalla (collegiate number 282873468), Gynecologist at Instituto Bernabeu