We used the 2013 Medicaid Analytic eXtract (MAX) database to estimate chlamydia testing rates separately for sexually active women aged 15-25 years who had, or had not, given birth in 2013. Approximately 9.2% of sexually active women aged 15-25 years gave birth in 2013. The Healthcare Effectiveness Data Information Set (HEDIS) annual chlamydia testing rate was significantly higher among women who had given birth than women who had not in 2013 (59.7 vs 29.4%, P<0.05). Our findings suggest a need for more research to understand how differences in population mix changes and preventive screening practices for pregnant and non-pregnant women affect publicly reported chlamydia screening rates.