The authors argue that despite a growing body of evidence that links vitamin D deficiency to complications in pregnancy and poor neonatal health, the UK remains the only one of 31 European countries that doesn’t have a set vitamin D recommendation for women of reproductive age, while also failing to endorse a daily supplement to expectant mothers.

Co-author Dr Elina Hyppönen, a reader in epidemiology and public health at the ICH, said: "The incidence of vitamin D deficiency in pregnant women in Britain is unacceptably high, especially during winter and spring. This is compounded by a lack of exposure to sunlight and the limitations of an average diet to meet the optimal need.

“In the most severe cases, maternal vitamin D deficiency can be life threatening to a newborn. We believe that the routine provision of a daily supplement throughout pregnancy would significantly decrease the number of mothers who are clearly vitamin D deficient, reducing related serious risks to their babies.

“Our take on vitamin D supplementation in the UK has seen many changes over the decades and we can see clearly from past experience that a proactive approach to supplementation has coincided with a much lower incidence of deficiency linked diseases such as infantile hypocalcaemia and rickets.”

Current data for the UK shows that women are more likely to be vitamin D deficient than men (9.2 and 6.6 per cent respectively). Pregnancy poses a particularly high risk situation, with one in four pregnant mothers being vitamin D deficient (below 25nmol/l) during winter and spring, with nearly all (90 per cent) having concentrations considered insufficient (below 50nmol/l).

In the article, Dr Hyppönen and her co-author, Barbara J Boucher (Queen Mary University of London), draw on historical data that supports the case for a daily dose of at least 10µg of vitamin D to prevent vitamin D deficiency in pregnant mothers, and recent evidence suggesting potentially wide-ranging benefits for the prevention of deficiency for the health of the mother and her child.

Dr Hyppönen said: “This risk of vitamin D deficiency is largely being overlooked by our health professionals. Under a current government scheme, pregnant women who are on a low income are entitled to receive supplements free of charge, but there is no strong evidence to suggest that this group are at greater risk. “What’s needed is a unified approach that will ensure that all expectant mothers, regardless of their economic status, are informed of the benefits of taking a regular supplement throughout pregnancy.”