The study, reported in the September 2013 European Journal of Clinical Nutrition, was conducted over a period of 20 years, and followed a cohort of 809 pregnant Danish women first recruited in 1988 and 1989. Researchers from the University of Iceland in Reykjavik, Aarhus University Hospital in Skejby, Denmark, and the Harvard School of Public Health in Boston, Mass., collaborated on the project, along with several Danish government agencies.
Initial findings confirmed that mothers who drank at least 5 ounces of milk per day while pregnant gave birth to bigger babies, which confirmed existing research. However, the scientists didn't stop there. Over the next two decades, they continued to monitor the children's growth into adulthood and found that, on average, those with mothers who had consumed the 5 ounces of milk during gestation were one-half inch taller than those who had not.
Researchers also concluded that those whose mothers drank the requisite amount of milk averaged higher blood levels of insulin-like growth factor, also called somatomedin C or IGF-1. The protein promotes healthy bone growth. While the average spike was about 8 percent, researchers found the instance to be statistically insignificant.
The study itself is significant, however, because it is among the first that connects pregnancy diets with a child's growth development.
"There aren't many prenatal dietary or environmental factors identified that explain growth in children. 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," said researcher Thorhallur Halldorsson, with the Center for Fetal Programming at the State Serum Institute in Copenhagen, reported by The New York Times.
So, how much milk should you drink while pregnant?
The U.S. Department of Agriculture outlined recommended dietary intake on ChooseMyPlate.gov. It's recommended that adults and children age 9 or older drink at least 3 cups of milk each day to stay healthy. Children between the ages of 4 and 8 should limit their consumption to 2.5 cups per day, while younger kids should consume only 2 cups.
The USDA also recommended that people opt for fat-free (skim) or low-fat (1 percent) milk.
Many people don't drink the recommended amount of milk each day, but opt for other calcium-fortified foods instead, such as orange juice or almond milk. Some individuals opt for calcium supplements, though researchers don't agree on whether the type of calcium found in supplements can be as readily absorbed into the body. If you're pregnant, talk to your doctor about what type of calcium best meets your needs.
Do you think drinking milk is important for baby development? Let us know your thoughts in the comments section!