New research has found that children whose mothers took extra vitamin D during pregnancy still have stronger bones at the age of seven.

Bone density scans from the study, led by the University of Southampton and University Hospital Southampton, revealed that these children's bones contained more calcium and minerals, making them stronger and less likely to break.

The researchers believe that the findings, published in The American Journal of Clinical Nutrition, highlight the importance of taking vitamin D supplements during pregnancy as a public health strategy.

Dr Rebecca Moon, an NIHR clinical lecturer in child health at the University of Southampton, said: "Our findings show that the benefits of vitamin D supplementation during pregnancy persist into mid-childhood.

"This early intervention represents an important public health strategy.

"It strengthens children’s bones and reduces the risk of conditions like osteoporosis and fractures in later life."

Vitamin D is vital for regulating the amount of calcium and phosphate in the body, which are essential for healthy bones, teeth, and muscles.

The Mavidos (Maternal Vitamin D Osteoporosis) study, launched in 2009, recruited more than 1,000 women from Southampton, Oxford, and Sheffield.

These women were randomly divided into two groups, with one group taking an extra 1,000 International Units of vitamin D per day during pregnancy and the other taking a placebo.

Neither the women nor their doctors and midwives knew which group they were in.

Previous research had shown that children born to mothers who took vitamin D supplements during pregnancy had greater bone mass at the age of four compared to those whose mothers did not.

The latest study followed up with 454 children aged six and seven from the Southampton area.

A University of Southampton spokesperson said: "The results confirmed that the beneficial effect on children’s bones was similar at ages four and six to seven.

"Pregnant women in the UK are now routinely advised to take vitamin D supplements."

The research was funded by Versus Arthritis, the Medical Research Council, the National Institute for Health and Care Research, and the Bupa Foundation.