Endocrine Abstracts

Vitamin D deficiency is a particular concern in pregnancy as it can affect both mother and infant, with problems lasting into childhood. A high prevalence of deficiency during pregnancy has been reported among known risk groups. Current guidelines on supplementing pregnant women are conflicting, with universal replacement recommended by the Department of Health but not supported by NICE guidelines. We aimed to determine the prevalence of vitamin D deficiency in a West London population. We measured 25-hydroxy vitamin D (25(OH)D) using ¹²⁵I radio-immunoassay in a prospective study of 57 12-week and 50 30-week pregnant subjects in March 2007. In addition, a retrospective casenote review of vitamin D assessment and replacement in 2531 deliveries between January-July 2006 was performed to assess current practice.

The median (interquartile range) 25(OH)D in the 12-week and 30-week cohorts was 36.0 (27.5–48.8) and 36.9 (26.6–58.8) nmol/l respectively (P>0.05, between groups). These levels are considered insufficient by most criteria. The prevalence of severe deficiency (25(OH)D <25 nmol/l) was 21.1% and 22% respectively and was greatest among non-white subjects compared to Caucasians in each cohort (55.6% vs 5.1%, P<0.001; 53.8% vs 10.8%, P=0.001). Asian subjects had the lowest 25(OH)D. In the retrospective study, only 30/2531 (1.2%) women had their vitamin D measured. Fourteen out of thirty had severe deficiency and thirteen of these were treated with oral supplements. Only two had repeat 25(OH)D assessment during pregnancy revealing borderline levels. These findings suggest that there are undetected, untreated and inadequately supplemented cases of vitamin D deficiency during pregnancy in our population. Suboptimal vitamin D levels were detected in Caucasians as well as in ‘high-risk’ ethnic minorities, lending support to universal replacement of vitamin D in pregnancy. Further intervention studies are required to clarify this issue and to determine the optimum treatment regimen.