Introduction
Routine prenatal human immunodeficiency virus (HIV) screening provides a critical opportunity to diagnose HIV infection, begin chronic care, and prevent mother-to-child transmission. However, little is known about the prevalence of prenatal HIV testing in the US-Mexico border region. We explored the correlation between prenatal HIV testing and sociodemographic, health behavior, and health exposure characteristics.

Methods
The study sample consisted of women who delivered live infants in 2005 in hospitals with more than 100 deliveries per year and resided in Matamoros, Tamaulipas, Mexico (n = 489), or Cameron County, Texas (n = 458). We examined univariate and bivariate distributions of HIV testing in Matamoros and Cameron County and quantified the difference in odds of HIV testing by using logistic regression.

Results
The prevalence of prenatal HIV testing varied by place of residence — 57.6% in Matamoros and 94.8% in Cameron County. Women in Cameron County were significantly more likely than those in Matamoros to be tested. Marital status, education, knowledge of methods to prevent HIV transmission (adult-to-adult), discussion of HIV screening with a health care professional during prenatal care, and previous HIV testing were significantly associated with prenatal HIV testing in Matamoros, although only the latter 2 variables were significant in Cameron County.

Conclusion
Although national policies in both the United States and Mexico recommend prenatal testing for HIV, a greater proportion of women in Cameron County were tested, compared with women in Matamoros. Efforts between Matamoros and Cameron County to improve HIV testing during pregnancy in the border region should consider correlates for testing in each community.