High incidence of asymptomatic genital tract infections in pregnancy in adolescent girls and young women: need for repeat aetiological screening.

INTRODUCTION

Sexually transmitted infection (STI) prevalence and incidence estimates for pregnant adolescents are under-reported. We estimated prevalence and incidence of STIs in pregnant adolescents (15-19 years) in comparison with pregnant women 20-24 and >25 years.

METHODS

Pregnant women registering at primary care clinics in Umlazi, a periurban subdistrict in KwaZulu-Natal, South Africa, were enrolled in an HIV incidence cohort study during February 2017-March 2018. Women were examined for abnormal vaginal discharge, received empirical treatment, tested for HIV-1 and had vaginal swabs taken at their first and a subsequent visit in the third trimester. Vaginal swabs were stored for STI testing at completion of study and tested for and using PCR.

RESULTS

A total of 752 HIV-negative pregnant women were enrolled at a median gestational age of 17 weeks: 180 (23.9%), 291 (38.7%) and 281 (37.4%) in the 15-19, 20-24 and >25 years age groups. Pregnant adolescents had an STI prevalence of 26.7% at baseline, not significantly lower than the 20-24 (34.7%, OR 1.4; 95% CI 1.0 to 2.1, p=0.09) and >25 years (33.8%, OR 1.4; 95% CI 0.9 to 2.1, p=0.12) age groups. (11.1%), (7.8%) and (4.4%) were most prevalent in adolescents, a trend similar to the other age groups. Overall, 43.4% were symptomatic and treated at baseline. Overall, 40.7% (118 of 290) of women who tested negative for an STI at baseline tested positive at the repeat visit (incidence 19.5/100 person years). STI incidence in pregnant adolescents was 23.9/100 person years and comparable with older age groups (20.5/100 person years and 16.2/100 person years). At the repeat visit, 19.0% of all women with an STI were symptomatic and treated. Performance of syndromic management was poor at baseline (negative predictive value (NPV) 68.6%, positive predictive value (PPV) 34.0%) and at repeat visit (NPV 58.4%, PPV 34.3%).

CONCLUSIONS

Prevalence of asymptomatic curable STIs in pregnant adolescents is high and comparable with women >20 years old. Adolescents remain at substantial risk of asymptomatic incident STIs during pregnancy.