Prevalence of Vitamin D Deficiency Among Iranian Pregnant Women

Background: Vitamin D deficiency (VDD) is a common concern. A high prevalence of VDD has been reported among pregnant women in different countries. The aim of this study was to assess the prevalence of VDD in the first trimester of pregnancy. Methods: This cross-sectional study was conducted on 267 pregnant women (before 14 weeks of gestation). The level of 25-hydroxyvitamin D (25(OH)D) was measured. Demographic data (age, educational level, season of blood sampling, and vitamin D supplementation intake) were collected using a questionnaire. Results: Based on the results of the study, 205 out of 267 subjects (76.8%) had deficient vitamin D levels (<20 ng/mL), 39 (14.6%) had insufficient levels (20-29 ng/mL), and 23 (8.6%) had sufficient levels (>= 30 ng/mL). In addition, 133 women (49.8%) had severe VDD. VDD was more prevalent in autumn/winter than in spring/summer (P=0.03). The prevalence of VDD was higher among the younger age group than in the older group (P=0.04). In multivariate analysis, the only variable that was significantly associated with low vitamin D status was taking supplements. Those who were not receiving vitamin D supplements had higher odds of VDD status (adjusted odds ratio=77.3, 95% CI 23.9-249.6). Conclusion: VDD is a public health problem in the first trimester of pregnancy. Greater awareness among healthcare providers and the community is required for prevention and appropriate treatment.