Taipei Tzu Chi Hospital Taipei, Taipei, Taiwan (Republic of China)
Objectives: Pregnant women are more prone to nutrient deficiencies due to fetal growth demands. Vitamin D deficiency, linked to preterm birth and gestational diabetes, is a major concern. In Taiwan, pregnant women have the same recommended vitamin D intake as healthy adults, sparking debates on supplementation necessity. This study explores how sunlight exposure levels, sunscreen use frequency, and dietary supplements affect serum 25(OH)D concentrations in pregnant women.
Methods: Sixteen pregnant women aged 18-45 were divided into normal (n=10) and gestational diabetes (n=6) groups. Blood samples were collected upon recruitment to measure serum 25(OH)D levels. Participants completed a questionnaire on supplement intake, sunlight exposure, and sunscreen use during pregnancy. Statistical analysis used Spearman rank correlation to assess relationships between biochemical values and serum 25(OH)D levels, with significance at p< 0.05.
Results: Previous studies have shown that exposure to sunlight for more than two hours results in sufficient vitamin D levels. It is also believed that the use of vitamin D supplements during pregnancy can maintain acceptable serum 25(OH)D concentrations. However, our study revealed no significant differences in serum 25(OH)D concentrations regardless of the length of sunlight exposure or frequencies of outdoor activities. No significant differences observed in the dosage of vitamin D supplements used, with a range from 50 to 200 IU/day. No subjects had an adequate level of serum 25(OH)D, with a mean of 18.2 ng/mL. Currently, the World Health Organization (WHO) encourages pregnant women to receive adequate sunlight exposure, and if not possible, to supplement with vitamin D at a dose of 200 IU/day, in order to reach desirable level of serum 25(OH)D.
Conclusions: Our study found that pregnant women in northen Taiwan were unable to increase their serum vitamin D levels through outdoor activities, avoidance of sunscreen, or intake of the recommended amount of vitamin D.
