Vitamin D Deficiency in Pregnant New Zealand Women

Aim: This aim of this study was to identify the prevalence of vitamin D deficiency in pregnant women of a Wellington general practice where 10 cases of childhood rickets had been diagnosed over the past 3 years.

Methods: Ninety pregnant women were screened for vitamin D deficiency by measuring 25-hydroxy vitamin D by DiaSorin radioimmunoassay. Recruitment into the study was over a 12-month period. A second appointment was arranged for clinical review and drawing of blood for parathyroid hormone, adjusted calcium, and alkaline phosphatase.

Results: 100% of women presenting to the general practice for antenatal care consented to the study. 87% of women had 25-hydroxy vitamin D levels below 50 nmol/L. 61.2% of women had a vitamin D level below 25 nmol/L consistent with severe vitamin D deficiency. 10 women had an elevated parathyroid hormone consistent with secondary hyperparathyroidism. Only 22% of our patients were veiled, and included a diverse ethnic population, including African, Maori, European, Middle Eastern, and Polynesian women.

Conclusions: Vitamin D deficiency is common in young pregnant women in this general practice, and it was not only confined to veiled women or women with dark skin. This highlights the magnitude of vitamin D deficiency in the pregnant population in a New Zealand setting; this vitamin D deficiency is responsible for the re-emergence of childhood rickets.