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Prevalence of vitamin D deficiency and insufficiency in pregnant women: a longitudinal study

Published online by Cambridge University Press:  17 March 2010

V. A. Holmes
Affiliation:
Nursing and Midwifery Research Unit, School of Nursing and Midwifery, Queen's University BelfastBT9 5BN, UK
M. S. Barnes
Affiliation:
Northern Ireland Centre for Food and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK
H. D. Alexander
Affiliation:
Department of Haematology, Belfast City Hospital, Belfast BT9 7AB, UK
P. McFaul
Affiliation:
Royal Jubilee Maternity Hospital, Grosvenor Road, Belfast BT12 6BW, UK
J. M. W. Wallace
Affiliation:
Northern Ireland Centre for Food and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK
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Abstract

Type
Abstract
Copyright
Copyright © The Authors 2009

Maternal vitamin D insufficiency is associated with childhood rickets and longer-term problems including schizophrenia and type 1 diabetes(Reference Holick1). Whilst maternal vitamin D insufficiency is common in mothers with highly-pigmented skin(Reference van der Meer, Karamali and Boeke2), little is known about the vitamin D status of Caucasian pregnant women.

The aim of the present study was to investigate vitamin D status in Caucasian pregnant women and non-pregnant age-matched controls living at 54°N–55°N. In a longitudinal study plasma 25-hydroxyvitamin D (25(OH)D) was assessed in ninety-nine pregnant women at 12, 20 and 35 weeks of gestation and in thirty-eighty non-pregnant women sampled concurrently.

Plasma 25(OH)D concentrations were lower in pregnant women compared with non-pregnant women at 20 and 35 weeks of gestation (P<0.0001). The percentage of pregnant women below the various cut-off values for vitamin D deficiency and insufficiency are presented in the Table.

* Data are cumulative.

While severe vitamin D deficiency (25(OH)D<12.5 nmol/l) was not apparent in the non-pregnant controls at any time-point, >95% of non-pregnant women were classified as insufficient at each time-point, assuming a cut-off of vitamin D insufficiency of <80 nmol/l. Vitamin D status was higher in pregnant women who reported taking multivitamin supplements at 12 (P<0.0001), 20 (P=0.001) and 35 (P=0.001) weeks of gestation than in pregnant non-supplement users; however, supplements did not prevent insufficiency (25(OH)D>50 nmol/l).

In summary, there is a high prevalence of both vitamin D deficiency and insufficiency in pregnant Caucasian women considered at low risk of vitamin D deficiency living at 54°N–55°N. Women reporting multivitamin supplement usage during pregnancy did have higher vitamin D status, but many remained vitamin D insufficient. Suboptimal vitamin D status has important consequences for maternal and neonatal health, and thus, further research is needed to determine the dietary vitamin D intake required to maintain vitamin D sufficiency during pregnancy and to underpin guidelines for supplement use during pregnancy.

References

1. Holick, MF (2004) Am J Clin Nutr 80, 1678S1688S.CrossRefGoogle Scholar
2. van der Meer, IM, Karamali, NS, Boeke, AJ et al. (2006) Am J Clin Nutr 84, 350353.CrossRefGoogle Scholar
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