Vitamin D levels in maternal serum and umbilical cord blood in a multi-ethnic population in Antwerp, Belgium

Objective: To describe the status of vitamin D levels in maternal and umbilical cord blood in term pregnant woman in a mixed ethnic population in an inner-city European maternity. Methods: A single centre prospective cohort descriptive study including all uncomplicated singleton term pregnancies from April 1, 2011 until May 31, 2011. Plasma 25-hydroxy vitamin D level was determined in maternal and umbilical cord blood and data on age, previous obstetric history, ethnicity, nutritional intake and use of vitamin supplements were registered. Results: Complete data were collected in 94 patients. Mean maternal serum vitamin D was 16.6 ng/mL. Using a cut-off of 20 ng/mL, 66% of women were classified as deficient. Deficiency was present in all ethnic groups, but lower levels were noted in North-African, Central-African and Asian women. A strong correlation between maternal and umbilical cord levels was noted (R = 0.91). Number of previous pregnancies and intake of supplements had no influence. Conclusion: The majority of low risk pregnant women showed vitamin D deficiency which was strongly correlated with umbilical cord levels. The prevalence was highest in the immigrant non-European population and was not influenced by intake of vitamin supplements. It can therefore be questioned whether the proposed cut-off values are appropriate.