Increased prevalence of human papillomaviruses in the lower genital tract of pregnant women.

In order to evaluate the influence of pregnancy on the presence of human papillomavirus (HPV) in the lower female genital tract, cervical smears of 92 pregnant and 96 non-pregnant women, matched by age, were examined for the presence of HPV-DNA by means of Southern blot hybridization. All patients had negative PAP smears. Twenty-six (28%) of the pregnant women and 12 (12.5%) of the non-pregnant women were positive for HPV. HPV 16 accounted for 42% of all positive pregnant cases and only 25% of the positive non-pregnant cases. Smears of pregnant patients contained more than 10 pg viral DNA in 45% of the cases against 20% in the non-pregnant group. HPV 16 showed the most active replication in both groups. This study demonstrates an increased prevalence of HPV (preferentially of HPV 16) and a higher replication rate of viral DNA during pregnancy.