A new study provides more evidence that HPV infection doesn’t raise the risk of poor outcomes in women who undergo fertility treatment via in vitro fertilization with fresh embryos. In fact, HPV-positive women were somewhat more likely than HPV-negative women to become pregnant (relative risk, 1.20; 95% confidence interval, 1.03-1.39) and have live births (RR, 1.39; 95% CI, 1.13-1.70), researchers reported Oct. 24 at the American Society for Reproductive Medicine’s 2022 meeting .
“This evidence should reassure women that being HPV positive will not affect live birth rates after a fresh embryo transfer cycle,” said study coauthor and ob.gyn. Nina Vyas, MD, a clinical fellow at Weill Cornell Medicine, New York, in an interview.
According to Dr. Vyas, previous studies have offered conflicting results about whether HPV affects pregnancy outcomes. In 2006, for example, her group performed a pilot study (Fertil Steril. Jun 16. doi: 10.1016/j.fertnstert.2006.01.051) that linked lower pregnancy rates to HPV-positive tests on the day of egg retrieval.
“We sought to reevaluate this finding in a retrospective manner,” Dr. Vyas said. “You’re taking eggs out of their home, injecting with sperm, and putting them back. There’s so much that we don’t know, and we want to make sure there’s no extra risk.”
Also, she added, “prior studies had a relatively low sample size. We sought to use our patient volume to address this question on a larger scale. Our current study benefits from a large sample size and using the clinically meaningful endpoint of live birth as our primary outcome.”
For the new study, researchers retrospectively analyzed 1,333 patients (of 2,209 screened) who received first fresh embryo transfers from 2017 to 2019. All had cytology or HPV status documented per cervical cancer screening guidelines within 6 months before embryos were transferred.
The researchers looked at only fresh embryo transfers “so we could account for pregnancy outcomes closest to the documented HPV status at the time of egg retrieval,” Dr. Vyas said.
Ten percent (133) of patients were HPV positive. Of those, 60.1% became pregnant, and 43.6% of them had live births. Of the HPV-negative women (90% of subjects, n = 1,200), 52.2% became pregnant and 33.5% had live births. The researchers didn’t calculate P values, but Dr. Vyas said an analysis determined that the differences between HPV-positive and HPV-negative women were statistically significant.
The study size doesn’t allow researchers to determine whether HPV actually has a protective effect on pregnancy/live birth rates in IVF, Dr. Vyas said. Even if it did, the virus is dangerous.
What else could explain the discrepancy? “Some elements driving this could the smaller sample size of the HPV-positive group, differences in HPV prevalence between the general population and our population,” she said, “or other confounding factors we were not able to appreciate due to the limitations of the retrospective study.”
Researchers also reported that they found “no significant difference in biochemical or spontaneous abortion rates” between HPV-positive and HPV-negative women.
What is the message of the study? “Women with HPV can rest assured that they won’t have worse outcomes than their non-HPV [infected] counterparts after a fresh embryo transfer cycle,” Dr. Vyas said.
In an interview, McGill University, Montreal, epidemiologist Helen Trottier, PhD, MSc, noted that she recently coauthored a study that linked persistent HPV infection in pregnancy to premature births. The findings appear convincing, she said: “I think we can say that HPV is associated with preterm birth.”
She praised the new study but noted “the relative risks that are reported need to be adjusted for race and possibly other factors.”
Dr. Vyas said that kind of adjustment will occur in a future study that’s in progress. “We are now prospectively enrolling patients and collecting cytology data to understand whether there might be a difference for women with higher malignancy potential/different types of HPV genotypes.”
The study authors have no disclosures. Disclosure information for Dr. Trottier was unavailable.