Dramatic decline in substance use by HIV-infected pregnant women in the United States from 1990 to 2012.

OBJECTIVE: We aimed to describe temporal changes in substance use among HIV-infected pregnant women in the United States from 1990 to 2012.
DESIGN: Data came from two prospective cohort studies (Women and Infants Transmission Study and Surveillance Monitoring for Antiretroviral Therapy Toxicities Study).
METHODS: Women were classified as using a substance during pregnancy if they self-reported use or had a positive biological sample. To account for correlation between repeated pregnancies by the same woman, generalized estimating equation models were used to test for temporal trends and evaluate predictors of substance use.
RESULTS: Over the 23-year period, substance use among the 5451 HIV-infected pregnant women sharply declined; 82% of women reported substance use during pregnancy in 1990, compared with 23% in 2012. Use of each substance decreased significantly (P < 0.001 for each substance) in an approximately linear fashion, until reaching a plateau in 2006. Multivariable models showed substance use was inversely associated with receiving antiretroviral therapy. Among the subset of 824 women with multiple pregnancies under observation, women who used a substance in their previous pregnancy were at elevated risk of substance use during their next pregnancy (risk ratio, 5.71; 95% confidence interval, 4.63-7.05).
CONCLUSION: A substantial decrease in substance use during pregnancy was observed between 1990 and 2012 in two large US cohorts of HIV-infected women. Substance use prevalence in these cohorts became similar to that of pregnant women in the general US population by the mid-2000s, suggesting that the observed decrease may be due to an epidemiological transition of the HIV epidemic among women in the United States.