HPV vaccination: Vaccinated women had fewer preterm births

Human papillomaviruses (HPV) are mainly transmitted through sex and can cause cervical cancer, among other diseases. Vaccination against them may have a further benefit: researchers at Karolinska Institutet in Stockholm analysed Swedish register data on 624,713 first pregnancies from 2006 to 2023 in the journal BMJ. Of the women, 92,620 had received the quadrivalent HPV vaccine before becoming pregnant.

Compared with unvaccinated women, the vaccinated women's risk of preterm birth was about 5 per cent lower, and the risk of very preterm birth about 15 per cent lower. Premature rupture of membranes and babies small for their gestational age were also less common. The associations were stronger when vaccination took place before the age of 17. "Our results suggest that the benefits of HPV vaccination may extend beyond cancer prevention," said researcher Jiayao Lei. Even a relatively small reduction in risk could matter at population level, Lei added.

The study is observational and cannot prove that the vaccine itself prevents preterm births, although the researchers adjusted for factors such as smoking, body weight, pre-existing conditions, income and education. Data on miscarriages were incomplete. One possible mechanism is that HPV infections and some cervical procedures are linked to pregnancy complications – this has not been confirmed. In Germany, the Standing Committee on Vaccination recommends HPV vaccination for girls and boys aged 9 to 14.