A new study suggests that the amount of milk a woman drinks during pregnancy may affect the adult height of her offspring.

Researchers followed 685 Danish mother-child pairs in a prospective study over 20 years, tracking milk consumption during pregnancy and the height of the offspring at birth and age 20. The study was published online Sept. 4 in The European Journal of Clinical Nutrition.

After adjusting for the mother’s height, age, body mass index and many other factors, they found that mothers who drank more than five ounces of milk a day — almost all drank low-fat milk — had bigger babies, on average, than those who drank less. This, the authors write, confirms the results of previous studies.

By age 20, children with mothers who drank more than five ounces of milk a day during pregnancy were, on average, almost a half-inch taller. They also had an average of 8 percent higher blood levels of IGF-1, or insulin-like growth factor, which promotes bone growth. But these trends did not achieve statistical significance.

“There aren’t many prenatal dietary or environmental factors identified that explain growth in children,” said Thorhallur Halldorsson, a researcher at Center for Fetal Programming at the State Serum Institute in Copenhagen. “Milk drinking may be one. It does increase weight and length at birth, and there’s a possibility that this actually tracks into adult life.”