Vitamin D deficiency during pregnancy: could additional supplementation provide long-term benefits for children’s health?

Estimates suggest that around one in three pregnant women in the UK may be vitamin D deficient.[1] Pregnant women who have low vitamin D levels during pregnancy have children with less mineral (calcium) in their bones, weaker muscles and more fat – increasing the risk of broken bones, osteoporosis (weak bones) and obesity. Dr Rebecca Moon of the University of Southampton is studying children whose mothers took part in a clinical trial to investigate if taking extra vitamin D during pregnancy provides long-term benefits for children’s health. Ultimately, this follow-up study could lead to a change in the NHS guidance on vitamin D supplementation during pregnancy – benefiting future generations of children.

How are children’s lives affected now?

Our bodies make vitamin D from sunlight on the skin and it is essential for our health, particularly for bone and muscle function. Low levels of vitamin D are very common in the UK – because many people don’t get enough time in the sun, especially during winter.

“In the UK, all pregnant women are already advised to take a 10-microgram supplement of vitamin D each day,” says Dr Moon. “This is because vitamin D supplementation may help to protect against certain pregnancy complications – but it may also provide benefits for the unborn child, such as improving bone and muscle health.”

Between 2008 and 2014, the researchers led the MAVIDOS Maternal Vitamin D Osteoporosis Study to investigate the potential benefits of taking extra vitamin D during pregnancy on children’s health.

“So far we have found that, by the age of four, the children born to mothers supplemented with vitamin D had more calcium – the mineral that gives bones their strength – and muscle than those whose mothers who received a placebo (dummy) drug,” says Dr Moon.

How could this research help?

“In this follow-up study, we now plan to establish if these differences seen at age four are still present at adolescence – a critical age for bone development due to puberty,” says Dr Moon.

The researchers will invite children born to women who took part in the MAVIDOS study – who are now between 11 and 14 years old – to attend a follow-up appointment.

“As well as assessing their bone mineral density, body composition and muscle function, we also hope to uncover new clues about how vitamin D exerts its effects on the developing child,” says Dr Moon.

The team will compare data from the children of mothers who took extra vitamin D during pregnancy with those of mothers who received the placebo – to determine whether additional supplementation has long-lasting effects on children’s health.

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