Predictors of HIV positivity among pregnant women presenting for obstetric care in South India - a case-control study.

Feminization of the HIV epidemic in India has increasingly burdened the public health infrastructure to provide prevention of mother-to-child transmission (PMTCT) services. A mere 20% of pregnant women in the country receive HIV counseling and testing. One of the strategies, for expansion of PMTCT services is to ascertain an accurate identification of HIV-positive pregnant women. Thus, we sought to characterize a demographic profile of pregnant women at high-risk for HIV infection. We performed a retrospective case-control study. We included as cases, all HIV-positive women identified in a PMTCT program implemented in 23 charitable faith-based hospitals in four states in South India over a period of 75 months, starting in January 2003. Thus a total of 320 HIV-positive cases were frequency matched using stratified random sampling to 365 HIV-negative pregnant women presenting for antenatal care during the same time period. Cases and controls were compared using Chi-square test for categorical variables and Student's t-test for continuous variables. Multivariate step-wise logistic regression analysis was performed. On multivariate analysis, following factors were independently predictive of HIV positivity: age ≤25 years (odds ratio [OR] 0.50; confidence interval [CI] 0.33-0.76; p = 0.001); illiteracy (OR 4.89; CI 2.79-8.57; p <0.0001); woman holding a service and/or professional job (OR 0.27; CI 0.14-0.53; p <0.0001); spouses holding a service or higher job (OR 3.13; CI 2.13-4.59; p <0.0001); being married ≤5 years (OR 2.89; CI 1.68-4.95; p <0.0001); late gestational age at presentation (OR 3.06; CI 2.04-4.59; p <0.0001); history of fetal and/or live born loss (OR 2.36; CI 1.51-3.67; p <0.0001). To our knowledge this is the first large study to evaluate factors predictive of HIV positivity among women presenting for antenatal care in the Indian setting. This type of profiling of HIV-positive pregnant women may help expand PMTCT services in a focused and cost-effective manner in India.