Prevalence, incidence and seroconversion of HIV and Syphilis infections among pregnant women of South Africa.

Background: Pregnant women in South Africa suffer from HIV and syphilis infections resulting in negative pregnancy outcomes. Little is known about the prevalence, incidence, seroconversion, and associated risk factors for those attending a midwife run obstetric unit.

Methods: A retrospective cohort study was undertaken among pregnant women attending antenatal clinic from January to December 2018. Logistic regression was conducted to determine the risk factors for HIV and syphilis.

Results: The prevalence of HIV and syphilis were 44.3% (95% confidence interval [CI]; 41.6:46.7) and 3.8% (95% CI; 3.1:4.1), respectively. The seroconversion and incidence for HIV were 4.0% (95% CI; 3.6:4.6) and 17.1 per 100 person-years, and for syphilis 2.6% (95% CI; 2.3:2.8) and 10.9 per 100 person-years, respectively. Significant predictors for HIV prevalence were ages: ages < 20 years, Odds ratio (OR) = 0.11 (p < 0.05), ages 20-24 years, OR = 0.19 (p < 0.05) and ages 25-29 years, OR = 0.38 (p < 0.05); gestational age: second trimester, OR = 0.68 (p < 0.05) and non-reactive syphilis, OR = 0.45 (p < 0.05). Age was the predictor for HIV incidence or seroconversion (age < 20 year, OR = 0.12, p = 0.01). Predictors for syphilis were ages < 20 years, OR = 0.11 (p < 0.05), ages 20-24 years and HIV status. Gestational age > 27 weeks were nine times (OR = 9.2, p = 0.03) more likely to seroconvert to syphilis.

Conclusions: The present study found high rates of seroprevalence, seroconversion and incidence of HIV and syphilis among pregnant women.