Vitamin D supplements for pregnant women could reduce osteoporosis in their children, according to research published on Friday.

The British study showed that children whose mothers lacked Vitamin D during pregnancy grow up to have weaker bones. A lack of Vitamin D is common in women of child-bearing age.

Professor Cyrus Cooper and a team from Southampton General Hospital in southern England studied almost 200 children born in 1991 and 1992. Their body size and bone mass were tracked up to the age of nine.

The study, published in The Lancet medical journal, showed that women who took Vitamin D supplements or who were exposed to higher levels of sunshine during pregnancy were less likely to be deficient in the vitamin.

“These findings provide evidence that maternal Vitamin D status during pregnancy influences the bone growth of the offspring,” Cooper said.