A recent study suggested that success rate of
may be reduced by over one half by the presence of infection with the virus, HPV. HPV infection may be an indicator of IVF failure.
Sexually transmitted infections can be the result of bacteria such as gonorrhea or chlamydia or viruses such as herpes, AIDs, and the human papilloma virus (HPV). HPV is the most common viral sexually transmitted disease affecting reproductive aged women. Each year, 30 million people contract the HPV virus according to the World Health Organization. In most women, HPV infections do not produce any illness or symptoms. In fact, in many women, their immune systems will clear apparently clear the virus from their bodies without any treatment. However, HPV infection is a common cause for PAP smear abnormalities and certain strains of HPV may cause cervical cancer. Occasionally, HPV may cause the development of genital warts.
Sexually transmitted diseases resulting from bacteria are a known major cause of infertility. Chlamydia infection, for example, has been identified as a cause for tubal obstruction and pelvic adhesions. The impact of HPV infection is less clearly understood.
HPV, Infertility and IVF
Only a few studies have evaluated HPV prevalence and its possible consequences in women. A German study found the rate of detection of HPV in women taking fertility drugs was similar to women without infertility. A study from Japan did not find a relationship between the presence of HPV and the success of IVF cycles. A Swedish study found similar rates of infection in in vitro fertilization patients compared to healthy women. If HPV were the cause of infertility or treatment failure, one would expect to find a higher incidence of infection in IVF patients than healthy women.
HPV IVF Study
This month, the medical journal Fertility and Sterility reported a study performed in New York. 106 patients who were going to undergo IVF treatment were studied. All of the women had a normal PAP smear in the 12 months prior to having their in vitro fertilization. None of the patients tested positive for HIV, chlamydia, gonorrhea, or syphilis. No active infections with herpes were noted. No viral warts were detected in these patients.
Prior to starting IVF, each patient was screening for HPV genetic material (DNA) by taking swabs of mucous from the cervical canal. A total of 18 strains were tested for; 13 of the most common strains that cause cancer (high risk) and 5 of the most common strains that don’t cause cancer (low risk).
Seventeen (16.0%) of the 106 women tested positive for HPV. This is a much higher incidence of infection than was reported in earlier studies. Compared to the 89 patients who tested negative, the two groups produced a similar number of eggs and mature eggs and there was no difference in the fertilization rate of the mature eggs. Each group had transfer of a similar number of embryos. Embryo quality also did not differ between the two groups.
However, patients with HPV were less likely to become pregnant after undergoing IVF. The pregnancy rate in HPV positive patients was 23.5%; in those without HPV it was 57%. There was no difference in the miscarriage rate. The cause for the reduction in pregnancy rate was not revealed by the study.
These results should be interpreted with caution for several reasons. First, the number of patients studied, especially those who tested positive for HPV was very small. Only 17 patients tested positive for HPV and there were only four pregnancies in that group. It is very difficult to generalize from such a small number. In addition, there are many more strains of HPV that were not detected by the assay used in the study. It is very possible that the non-HPV group may nonetheless be infected with one of these other strains.
Recently, a vaccine has been made available that may prevent infection with some of the more common cancer causing strains. In order to be effective, these vaccines must be given to women before the onset of sexual activity. There is no known cure for women who currently are infected with HPV. Furthermore, since the possible mechanism causing infertility is unknown, there is no therapy available to help improve the chances for pregnancy. For these reasons, at this time, routine testing of infertile women for HPV is not indicated.