Fetal alcohol exposure data underscore need for public health interventions

While alcohol consumption during pregnancy may result in harm to developing embryos and fetuses, a new study led by the Yale School of Public health finds that a significant number of pregnancies that result in live birth still involve alcohol exposure.

Researchers led by Reza Yaesoubi estimate that 54% of pregnancies that result in a live birth are exposed to at least one alcoholic drink during the nine-month gestation period, that 12% are ever exposed to five or more drinks in a week, and 3% are ever exposed to nine or more drinks in a week.

Yaesoubi and his team used a computer simulation model of U.S. women of reproductive age to determine what proportion of pregnancies that result in live birth in the United States are exposed to alcohol. Their results are published in the journal Medical Decision Making.

“Finding that more than half of pregnancies that result in a live birth are exposed to alcohol was a big surprise; so we tried to understand what is contributing to this,” said Yaesoubi, an assistant professor in the Department of Health Policy and Management.

“When we consider alcohol-exposed pregnancies, much of the focus is on women who are aware of their pregnancies but may continue to drink,” he said. “But what we found in this study is that among pregnancies that are exposed to alcohol, in fact, more than half are exposed while the pregnancy is still unrecognized.”

Unintended pregnancies (either due to contraceptive failure or sex without the use of contraception) account for 80% of pregnancies unknowingly exposed to alcohol, Yaesoubi and his research team estimate. They also project that public health efforts that focus only on promoting alcohol abstinence among women who are aware of their pregnancy or seeking pregnancy could reduce the prevalence of alcohol-exposed pregnancies by at most 42%. Augmenting this strategy with efforts to avert unintended pregnancies could yield an 80% reduction in the prevalence of alcohol-exposed pregnancies.

Alcohol use during pregnancy is associated with a range of adverse outcomes and can cause fetal alcohol spectrum disorders (FASDs) that are characterized by lifelong physical, behavioral, and intellectual disabilities. Approximately 1% to 5% of the U.S. population is affected by FASD. Not every pregnancy that is exposed to alcohol results in a child with FASD, but in the absence of a scientifically proven safe threshold for fetal alcohol exposure, preventing alcohol-exposed pregnancies remains the key tactic to avoiding FASDs.

The findings underscore the need for integrated efforts to prevent alcohol-exposed pregnancies that both seek to prevent unintended pregnancies and promoting alcohol abstinence among women who are pregnant or seeking pregnancy.

The research was supported by grants from the Agency for Healthcare Research and Quality, the National Institute on Drug Abuse, and the National Institute of Allergy and Infectious Diseases. Associate Professor Mona Sharifi at the Yale School of Medicine and Professor A. David Paltiel at the Yale School of Public Health co-authored the paper.