Rate of low vitamin D levels in a low-risk obstetric population

The objectives of this study were to determine vitamin D levels at the first prenatal visit in women who had no obstetric risk factors and, if determined to have a low vitamin D level, to evaluate how high-dose treatment affected the vitamin D level by the end of the second trimester.

This study was a descriptive, retrospective chart review. Women were identified through electronic database query based on prenatal care initiation. One hundred and four women had a 25-hydroxy (OH) vitamin D (25[OH]D) serum level drawn at the first prenatal visit. Supplementation was recommended with either 2000 or 4000 units of vitamin D3 for women who had vitamin D insufficiency or deficiency. Twenty women who were treated had repeat vitamin D levels drawn at 28 weeks' gestation to evaluate the effectiveness of supplementation.

Descriptive analysis of demographic data of 104 women who had 25(OH)D levels drawn determined there were no significant differences between women who were vitamin D deficient or insufficient and those whose serum levels were in the sufficient range. Vitamin D serum levels revealed that 32 (30.8%) were sufficient (>30 ng/mL), 49 (47.1%) were insufficient (20-29 ng/mL), and 23 (22.1%) were deficient (<20 ng/mL). Twenty women had a repeat measure of 25(OH)D after supplementation, and there was a significant rise in vitamin D level (P < .001) with vitamin D3 supplementation. However, women who took 4000 units had a higher mean rise (13.17 ng/mL) in 25(OH)D than those taking 2000 units (8.79 ng/mL). Twelve of the women (60%) were still insufficient after supplementation with 2000 units of vitamin D3 .

This small sample of women demonstrates a significant degree of insufficiency and deficiency in this desert community where sunshine is plentiful. A larger study should be completed to determine ideal supplementation during pregnancy.