Objective:

The aim of this study was to determine the prevalence and the predictive factors of vitamin D deficiency in pregnancy and the compliance with “The National Vitamin D Support Program” at Turkey’s easternmost and westernmost provinces.

Material and Methods:

Lifestyles of women at 24-28 weeks of pregnancy were assessed using a questionnaire form, and serum 25-hydroxyvitamin D3 (25(OH)D3) levels were measured.

Results:

Vitamin D deficiency (≤20 ng/mL) in pregnant women had a prevalence of 27.8% in İzmir and 76.3% in Erzurum. The compliance of “The National Vitamin D Support Program” was 8% in İzmir and 32.6% in Erzurum. Clothing style, fish consumption, seaside holiday duration, and 1200 IU/day vitamin D replacement had an effect on 25(OH)D3 levels in pregnant subjects in İzmir, whereas only holiday duration and 1200 IU/day vitamin D replacement affected 25(OH)D3 levels in Erzurum. However, when a threshold for 25(OH)D3 level was considered ≥32 ng/mL, lifestyles did not affect 25(OH)D3 level.

Conclusion:

The effect of lifestyle on 25(OH)D3 level in pregnancy is limited, especially in cold regions. We recommended increasing the compliance with “The National Vitamin D Support Program” at the follow-up of all pregnant women, irrespective of region and season.

Keywords: Pregnancy, vitamin D deficiency, vitamin D replacement, lifestyle, place of residence