by Michael Woodhead  

Sexually active women seeking HPV vaccination should be advised to use contraception until one month after the third dose, reproductive health specialists say.  

While there appear to be no increased risks of the vaccine in pregnancy, specialists have expressed some concern about potential adverse pregnancy outcomes in women who conceive within 30 days of vaccination.  

A study in Obstetrics and Gynecology (114: 1168-9) co-authored by Dr Suzanne Garland of the Royal Women’s Hospital in Melbourne, has found a slightly higher rate of congenital abnormalities in infants of 3620 women involved in clinical trials of the quadrivalent vaccine.

The difference was not significant, and independent teratology experts determined that the anomalies were unlikely to be causally related to vaccination.  

A second study of 517 pregnancy outcomes after HPV vaccination  found a slightly higher fetal death rate and four cases of CNS malformations or neural tube defects but no increase in major birth defects.  

An accompanying editorial says the new data do not suggest a significant increase in risk for women who have received the vaccine shortly before conception, but it cannot be ruled out.

They say the findings are preliminary and subject to bias, but given the widespread use of the vaccine and the high stakes involved, a cautious approach to conception similar to that seen in the clinical trial volunteers should be adopted.  

“At the current state of evidence, a cogent argument can be made to also recommend that women at risk of pregnancy seeking HPV vaccination be advised [to use effective contraception until one month after the third dose]," it concludes.