High Prevalence of Vitamin D Deficiency in Pregnant Korean Women: The First Trimester and the Winter Season as Risk Factors for Vitamin D Deficiency

Abstract

We investigated the vitamin D status of Korean women during pregnancy and assessed the effects of vitamin D deficiency on two pregnancy outcomes; preterm births and the births of small for gestational age. We measured the serum 25-hydroxyvitamin D levels in 220 pregnant Korean women who were recruited prospectively and compared these levels with those of 500 healthy non-pregnant women. We analyzed vitamin D status according to patient demographics, season, and obstetrical characteristics; moreover, we also assessed pregnancy outcomes. The overall prevalence of vitamin D deficiency(<20 ng/mL) in pregnant women and healthy non-pregnant women was 77.3% and 79.2%; respectively; and the prevalence of severe vitamin D deficiency (<10 ng/mL) was 28.6% and 7.2%; respectively (p < 0.05). Vitamin D deficiency was more prevalent in the winter (100%) than in the summer (45.5%) in pregnant Korean women. A higher risk of vitamin D deficiency was observed in the first trimester than in the third trimester (adjusted OR 4.3; p < 0.05). No significant association was observed between vitamin D deficiency and any of the pregnancy outcomes examined. Further research focusing on the long-term consequences of vitamin D deficiency during pregnancy in Korean women is warranted.

Vitamin D and risk of preterm birth: Up‐to‐date meta‐analysis of randomized controlled trials and observational studies

“…The score for one article, however, was unable to be evaluated because the full text was not available, and three RCT had low risk of bias. Table 1 lists the characteristics of the 18 observational studies 9,[12][13][14][15][16][17][18][19][20][21][22][23][24][30][31][32] and six RCT. [33][34][35][36][37][38] There was some disparity in the definition of PTB between studies.…”

“…8 In a survey of Asian subjects, 77.3% had circulating 25-OHD concentration < 50 nmol/L, and 28.6% had concentration <25 nmol/L. 9 Lower maternal vitamin D status during pregnancy is a risk factor for various adverse birth outcomes including PTB. 10 Epidemiologic studies and randomized trials concerning the association of maternal hypovitaminosis D during pregnancy and PTB yielded mixed results.…”

“…11 Most observational studies, however, did not show a significant relationship. 9,[12][13][14][15][16][17][18][19][20][21][22][23][24] A trial of vitamin D supplementation suggested that 25-OHD serum concentration > 100 nmol/L (vs <50 nmol/L) could significantly reduce the risk of PTB. 25 Other studies, however, did not obtain the same results.…”

Maternal Anemia and Vitamin D deficiency: associations with neonatal hemoglobin levels and the vitamin D status

“…1,2 The results from previous studies indicated that the vitamin D levels in Korean preterm infants were lower than those in infants in Northern European countries. 3,4 Vitamin D deficiency remains a common micronutrient disorder despite of encouragement to vitamin D supplements.…”

Vitamin D Status in Pregnancy: Fetomaternal Outcome and Correlation with Cord Blood Vitamin D

“…1 The high prevalence of vitamin D insufficiency during pregnancy is increasingly recognized, especially in dark women, following customs like veil, in women living in northern latitudes and during winter season. 1,3,4 Maternal effects of hypovitaminosis D have been reported to cause calcium malabsorption, bone loss, poor weight gain, subclinical myopathy, 5 increased preeclampsia (PE), 6 increased gestational diabetes mellitus (GDM), 7 increased cesarean sections. 8 In the newborn, hypovitaminosis D has been reported to cause neonatal tetany, 9 hyperbilirubinemia, 10 large fontanelle, enamel defects, congenital rickets, and infantile rickets.…”