Winter and weight gain can reduce effectiveness of vitamin D in pregnant women

THE effectiveness of vitamin D supplements during pregnancy depends on the season and the mother’s weight gain, according to a study.

Research suggests supplements are less effective at raising vitamin D levels in women if they deliver their babies in the winter, have low levels of the vitamin early in pregnancy or gain more weight before giving birth.

Professor Nicholas Harvey, of Southampton University, said: “It is important for pregnant women to have sufficient levels of vitamin D for the health of their baby.

“Our study’s findings suggest that in order to optimise vitamin D concentrations through pregnancy, the supplemental dose given may need to be tailored to a woman’s individual circumstances, such as the anticipated season of delivery.”

Vitamin D helps the body absorb calcium and plays a crucial role in bone and muscle health.

The skin naturally produces vitamin D after exposure to sunlight but people also obtain smaller amounts of the vitamin through foods, such as milk fortified with vitamin D.

Evidence suggests vitamin D deficiency during pregnancy can harm maternal health, foetal development and the child’s long-term skeletal health.

More than 800 pregnant women were recruited for the study.