There may be many more children than previously thought with developmental disabilities resulting from alcohol exposure during pregnancy, researchers say. (Bob Fila/Chicago Tribune/MCT)

New research suggests that fetal alcohol spectrum disorders may be far more common than previously thought.

The developmental disability, which results from drinking alcohol during pregnancy, may affect as many as 5 percent of children, according to findings published this month in the journal Pediatrics.

For the study, researchers examined the prevalence of fetal alcohol spectrum disorders among first graders enrolled in public and private schools in Sioux Falls, S.D.

More than 1,400 kids participated in initial screenings. Then, researchers identified two groups of children for more extensive assessments — some of whom were randomly chosen and others who were identified because they were small for their age.

Those selected for further study were given exams to measure physical growth, development, dysmorphology, cognition and behavior. What’s more, their mothers were interviewed about their exposure to alcohol while pregnant.

Ultimately, physical and cognitive assessments indicated that 2.4 percent to 4.8 percent of the kids studied had some form of fetal alcohol spectrum disorders, researchers said.

Mothers of those flagged for the condition reported higher levels of weekend binge drinking prior to learning they were pregnant as well as less frequent and delayed prenatal care. What’s more, the study found that these moms were also more likely to indicate that the children’s fathers drank often.

“Previous estimates of fetal alcohol spectrum disorders put the occurrence at around 1 percent in the United States,” said Gene Hoyme of Sanford Research and The University of South Dakota who worked on the study. “By actively assessing the children who were part of this study, our team was able to develop a more accurate figure for the prevalence of this disorder among the predominately middle-class population of Sioux Falls and identify key risk factors that can predict it.”

Fetal alcohol spectrum disorders include a range of conditions that are caused by prenatal exposure to alcohol and can result in a variety of physical symptoms including small size, poor coordination and abnormal facial features as well as behavior and learning issues.

The disorders are “completely preventable,” according to the U.S. Centers for Disease Control and Prevention, so long as pregnant women do not consume alcohol.