Prevalence and Incidence of Human Papillomavirus (HPV) Infection Before and After Pregnancy: Pooled Analysis of the Control Arms of Efficacy Trials of HPV-16/18 AS04-Adjuvanted Vaccine

Objective: Data on human papillomavirus (HPV) prevalence around pregnancy were inconsistent. We assessed HPV prevalence before and after pregnancy, HPV incidence after pregnancy, and risk factors for HPV infection.

Method: Data from 15 754 women in control arms of 5 AS04-HPV-16/18 vaccine efficacy trials were analyzed, including 3001 women with at least 1 pregnancy. Results of HPV deoxyribonucleic acid testing on cervical samples were available. We analyzed risk factors, including age, region, pregnancy and its outcomes, duration from pregnancy resolution to collection of first postresolution cervical sample, previous HPV infection, cigarette smoking, and number of sexual partners with Cox regression.

Results: Prevalence of high-risk oncogenic (hr)-HPV types was similar before and after pregnancy (20.8% vs 19.8%). Incidence of hr-HPV was 40.1 per 1000 person-years (95% confidence interval [CI], 23.4-64.2) at 0-3 months, 266.7 (95% CI, 217.4-323.7) at 3-6 months, and 95.7 (95% CI, 83.9-108.7) at >6 months after pregnancy. Risk factors associated with HPV infection after pregnancy are previous HPV infection, elective abortion, and younger age at pregnancy resolution.

Conclusions: Pregnancy could not be confirmed as a risk factor for HPV infection in this population despite an increased incidence detected 3-6 months after pregnancy resolution. Most women remained HPV negative after pregnancy.

Clinical trial registration: NCT001226810 (HPV-008 trial), NCT00294047 (HPV-015 trial), NCT00316693 and NCT00929526 (HPV-032/063 trials), and NCT00779766 (HPV-039 trial).