Prevalence of Vitamin D Deficiency in Pregnant Women in Ayrshire: An Exploratory Study

  • Ruth Campbell

Student thesis: Doctoral ThesisProfessional Doctorate (ProfD)


Vitamin D deficiency among pregnant women is a global issue, however, the prevalence among local women is not known. The aim of this study was to assess vitamin D status among pregnant women in Ayrshire and the effect of vitamin D supplementation on their vitamin D levels. Serum 25-hydroxy vitamin D (25(OH)D) levels were measured at 12 and 34 weeks gestation in two groups of women (n = 612). To assess seasonal variation, one group was recruited in summer, the other in winter. Demographic data were collected to assess the impact of such factors on vitamin D levels.

Median serum 25(OH)D levels at 12 and 34 weeks were 61 nmol/1 (IQR 40) and 81 nmol/1 (IQR 51), respectively. Season, uptake of vitamin D supplements, age,deprivation and smoking status all had a significant impact on vitamin D levels. At 12 and 34 weeks, 36.4% and 22.7% of women had a serum 25(OH)D < 50 nmol/1,respectively. Women in early pregnancy during the winter were 5.37 times more likely to be insufficient in vitamin D compared to those in early pregnancy in the summer(AOR; 95% Cl: 5.37; 3.48, 8.29, p < 0.001). Sixty six percent of women reported taking a vitamin D supplement as recommended. Younger women (p < 0.001), those who lived in the most deprived areas (p < 0.001) and those who smoked (p < 0.001)were least likely to have taken a supplement. Women who did not take a supplement were 7.72 times more likely to be insufficient in vitamin D in late pregnancy compared to those who took a supplement as recommended (AOR; 95% Cl: 7.72; 4.36, 13.66, p <0.001).

Although 10 pg of vitamin D improved women’s vitamin D status during pregnancy, it was not an adequate dose to ensure all those insufficient in vitamin D at 12 weeks achieved sufficient status at 34 weeks. Further studies are required to establish the dose that maintains adequate vitamin D levels throughout pregnancy and the benefit this confers on clinical outcomes for mothers and babies in the short and longer term.
Date of Award2017
Original languageEnglish
Awarding Institution
  • Glasgow Caledonian University
SupervisorAndrew Collier (Supervisor) & Julie Armstrong (Supervisor)

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