Vitamin D deficiency in Mongolian pregnant women

We aimed to estimate the prevalence of vitamin D deficiency in Mongolian pregnant women at the National level as part of the Fifth National Nutrition Survey 2016.

This was a cross - sectional survey, conducted between September and November in 21 Aimags of 4 economic regions of the country, and in Ulaanbaatar. Given the regional differences in lifestyle and nutritional status, the target populations were stratified into 5 strata based on their economic region and in Ulaanbaatar, with equal samples drawn from each stratum using a cluster - randomized sampling design. A representative sample of 30 clusters was randomly selected using Probability Proportional to Size [PPS] methodology in each of the 4 regions and Ulaanbaatar for a total of 150 cluster units. The selection of survey participants differed for the three sampling regions. Household eligibility was based on having a child 0-59 months of age, living in the household which was randomly selected from each cluster for a total of 450 households in each region. Households with a child 0-59 months of age were selected from household lists available at the kheseg or Bagh level. All pregnant women were selected randomly from Soum and Khoroo family health center antenatal care registries who were mothers of a family with children aged from 0 to 5 years old.

We conducted a cross - sectional survey evaluation of 924 pregnant women who were mothers of a family with children 0-5 years old.

Serum concentration of 25 - hydroxyvitamin D [25(OH)D] were measured using an enzyme-linked fluorescence assay.

The overall prevalence of vitamin D deficiency was 75.4% (95% CI 72.2-78.4) with no significant difference in the prevalence of vitamin D deficiency by age group, economic region, area, location, education, ethnicity and body height statuses. Also, prevalence of vitamin D deficiency was 71.9% (95% CI 60.3-81.1), 77.5% (95% CI 60.3-81.6) and 74.2% (95% CI 69.2-78.7) in the first trimester, second trimester and third trimester of pregnancy with no significant difference in the prevalence of vitamin D deficiency between the trimesters of pregnancy. Only 7.3% of pregnant women took a specific vitamin D supplement, with 31.5% of these starting in the first trimester and 60.9% of pregnant women starting supplementation in the second trimester. There is currently no vitamin D food fortification in Mongolia, and oral vitamin D intake across the whole population is very low. The findings of this survey showed that vitamin D deficiency in pregnant women is a public health problem in Mongolia. In conclusion, vitamin D deficiency and low vitamin D status are common in Mongolian pregnant women, which indicated the essential need to include vitamin D screening with adverse maternal and fetal outcomes, and a requirement needed to implement empirical vitamin D supplementation programs before food fortification with vitamin D.