Prevalence of 'high risk' human papillomavirus in the lower genital tract of Brazilian gravidas.

The presence of high-risk human Papillomavirus types 16, 18 and 33 was examined in 125 pregnant patients with abnormal Papanicolau smears. Specimens of cervicovaginal cells were analyzed by a simplified method of slot-blot hybridization. The overall prevalence of those viral sequences was 48%, being: 22.4% of HPV16, 17.6% of HPV18, 4.0% for double HPV16 and 18 infestation and 4.0% of HPV33. Their prevalence in HPV positive cervical sample was alone respectively 46.6%, 36.6%, 8.3% and 8.3%. Besides the high incidence of those carcinogenic types and intense viral proliferation, a rapid progression from CIN to carcinoma was clinically observed in four pregnant patients. Our data may reinforce the idea that progesterone has a positive role to the persistence and transformation of 'high risk' HPV, particularly of HPV16. The enhanced detection of potentially malignant types during pregnancy should warn on the importance of early diagnosis and treatment of papillomatosis.