Estimating the Prevalence of United States Women with Alcohol-exposed Pregnancies and Births.

AIMS: Researchers at the U.S. Centers for Disease Control and Prevention (CDC) recently estimated the number of women at risk for alcohol-exposed pregnancies (AEPs) as 3.3 million per month. The number of women at risk was widely interpreted as the actual number of AEPs. The actual number of AEPs may be easier to interpret and may be more a more relevant public health metric for evaluating efforts to reduce AEPs. We estimated the expected actual number of AEPs among U.S. women 15-44 years of age and the expected actual number of alcohol-exposed births (AEBs).

METHODS: Like the CDC researchers, we used data about women aged 15-44 years who were neither pregnant nor sterile from the 2011-2013 National Survey of Family Growth. We identified women who had had sex without contraception in the last 4 weeks and reported binge drinking or drinking on more than 7 of the last 30 days. We then estimated the expected actual number of AEPs and AEBs, accounting for the chances of becoming pregnant and for pregnancy outcomes (birth, miscarriage, and abortion). We also conducted sensitivity analyses with varying assumptions.

RESULTS: Estimated prevalences of AEPs and AEBs were 1.2% (95% confidence interval, 0.9-1.7) and 0.8% (95% confidence interval, 0.5-1.2), respectively. During a 1-month period, we estimate 731,000 U.S. women had AEPs and 481,000 resulted in AEBs. Sensitivity analyses indicate expected actual AEP estimates ranging from 104,000 to 1,242,000 and AEBs from 79,000 to 816,000.

CONCLUSIONS: Under our assumptions, the estimated expected actual number of AEPs is 2.5 million less than the CDC estimate of the number at risk of an AEP. By using evidence-informed assumptions for the chances of becoming pregnant and common pregnancy outcomes, our estimate of the expected actual number of AEPs is only 22% as large as the CDC's estimate of number at risk, and our estimate of expected actual number of AEBs only 15% as large. The evidence-informed assumptions used here should inform future efforts to estimate expected actual numbers of AEPs and AEBs.