Between 1 and 5 percent of first-graders have fetal alcohol spectrum disorders, according to new research from the National Institute on Alcohol Abuse and Alcoholism.

The institute studied more than 6,000 first-graders across four U.S. communities has found that a significant number of the children have fetal alcohol spectrum disorders. According to a release from the National Institutes of Health, the study findings represent more accurate prevalence estimates of FASD among general U.S. communities than prior research. Previous FASD estimates were based on smaller study populations and did not reflect the overall U.S. population.

FASD is an umbrella term for a range of health effects caused by prenatal alcohol exposure. Individuals with FASD may experience growth deficiencies, facial abnormalities, and organ damage, including to the brain. The effects of prenatal alcohol exposure on the brain can result in a range of neurobiological deficits that contribute to physical, cognitive, behavioral, and social challenges throughout life.

“Prenatal alcohol exposure is a leading preventable cause of developmental disabilities worldwide,” said NIAAA Director George F. Koob, in news release. “Estimating the prevalence of FASD in the United States has been complex due to the challenges in identifying prenatally exposed children. The findings of this study confirm that FASD is a significant public health problem, and strategies to expand screening, diagnosis, prevention, and treatment are needed to address it.”

Researchers collected data between 2010 and 2016 on 6,639 children in four communities in the Midwest, Rocky Mountain, Southeast and Pacific Southwest, sites that were selected to be more reflective of U.S. community populations than previous studies. At each site, first-graders in public and private schools were recruited across two academic years and evaluated based on the FASD criteria. Prenatal alcohol exposure was assessed by interviewing mothers or other close relatives.

The researchers found that the prevalence estimates for FASD among the selected sites ranged from 1.1 to 5 percent. This was the most conservative estimate and assumed that no additional cases of FASD would be found in first-graders who did not participate in the study.

Though Connecticut was not included in the study, Centers for Disease Control and Prevention statistics from 2015 showed that drinking among women of child-bearing age in the state is relatively high. The research showed that 61 percent of women between 18 and 44 reported consuming any alcohol use in the past 30 days and 17.1 percent reported binge drinking — four or more drinks on a single occasion — during the past 30 days.