Widespread vitamin D deficiency among pregnant women suggests that antenatal screening for deficiency should be extended to all women, not just those traditionally considered to be at high risk, Australian researchers say.

A study in a region of northern Victoria found that around 80% of low-risk pregnant women have insufficient vitamin D levels, 28% have mild deficiency during the winter months and 7% have moderate to severe deficiency.

The study of more than 330 women attending routine antenatal clinics in Shepparton also found that deficiency was also present in the summer months, with 50% of pregnant women having insufficient vitamin D levels (between 50 and 75mmol/L), 12% having mild vitamin D deficiency (25-50mmol/L) and 3% having moderate to severe deficiency.

The findings, published in the Australia and NZ Journal of Obstetrics and Gynaecology may explain why some children in the region still develop rickets even though there is abundant sunshine, say the study authors from the Rural Clinical School of the University of Melbourne. They note that vitamin D deficiency was almost universal in women in their study who were from high risk groups such as those from Arabic backgrounds.

“However, our study would support routine testing for all antenatal women, as even apparently low risk women are commonly vitamin D deficient,” they write. The only question remaining is over the optimum level of supplementation, they say, with some doubt about whether the daily supplements of 800IU of vitamin D a day may be insufficient to raise vitamin D levels.