The human papillomavirus vaccine is created to protect young women from cervical cancer and other types of tumors.
The vaccine, developed by Sanofi Pasteur and distributed under the market name Gardasil, is intended for girls and women aged between 9 and 26, but it's not recommended during pregnancy.
In some cases, the patients prove to be already pregnant and without being aware of it at the time of the immunization, which experts say can occur quite frequently, considering the vaccine is administered in women's "reproductive window."
No Risk Of Major Birth Defects
Any potential concerns that vaccination during early pregnancy can be dangerous to the fetus and cause congenital abnormalities have now been put to rest by a recent Danish study.
Authored by researchers from the Statens Serum Institute in Copenhagen, the paper documents the quadrivalent HPV vaccine poses no health treats in the off-chance it is administered to pregnant women.
The team examined data from various national registries and analyzed all pregnancy files registered in Denmark in the span of seven years, from 2006 and 2013.
The investigation compared 1,665 women who received Gardasil during early pregnancy with 6,660 women who were not pregnant at the time of vaccination.
The results showed the HPV vaccine doesn't increase the chances of major birth defects, spontaneous miscarriage, preterm delivery, stillbirth, and low weight at birth or compared to the gestational age.
"Our results do not support that this exposure [to HPV vaccination] has an adverse effect on the unborn baby," Dr. Anders Hviid, study co-author and epidemiologist at the Danish institute, said in a statement.
Still Not Recommended During Pregnancy
The new study, published in the New England Journal of Medicine, offers valuable information concerning the safety of HPV vaccines for expecting mothers. Prior to this research, the available information on the subject was relatively scarce.
Yet, although the paper clearly states Gardasil is not harmful when inadvertently administered during pregnancy, health regulators don't intend to change the immunization guidelines. So far, the vaccine remains not recommended for pregnant women.
One reason is that further analysis is needed to cover all bases of the vaccine. For instance, the Danish study didn't assess the safety of Gardasil's bivalent version, which targets fewer strains of the virus.
A previous study linked this version of the HPV vaccine to a higher rate of spontaneous abortion for up to 90 days after immunization, although follow-up research didn't confirm the hypothesis.