“I would like to point out that the increase in risk for preterm birth is small for the individual woman carrying HPV,” said researcher Johanna Wilk. “But our results support that young people should get into the vaccination program against HPV.”
Understanding preterm birth risk
For the study, the researchers analyzed data from more than 1 million births recorded in the Swedish Medical Birth Register. They also looked at mothers’ medical histories using the National Quality Registry for Cervical Cancer Prevention and the Swedish Cancer Register.
The team was interested in both HPV infection and treatment of cervical intraepithelial neoplasia (CIN), which occurs when there are abnormal changes to cervical cells related to HPV infection. Nearly 12,000 of the participants were infected with HPV, and more than 23,000 women had been treated for CIN.
The researchers learned that nearly 6% of women with HPV delivered prematurely, compared to 4.6% of women with no history of HPV. Additionally, more than 9% of the women who had received treatment for CIN had preterm births.
“Our study is register-based and, although we’ve adjusted for various factors in the analyses, we can’t reliably answer the question of whether it’s the virus itself that causes the pregnancy and childbirth complications,” said researcher Verena Sengpiel. “All we can do is show a statistical association.
The researchers hope that more women are treated and tested when their doctors notice abnormal changes in cervical cells due to HPV infection. Doing so could help increase the chances that women have a healthy pregnancy and successful delivery.
“The earlier these abnormal changes are detected, the better we can follow and treat them,” Wilk said. “And when you’re admitted to maternity care, it’s a good idea to tell your midwife if you’ve had cervical cell changes, and whether you’ve been treated for them. Then the maternity health staff can take that information into account when planning the monitoring of your pregnancy.”