The Association Between Levels Of Serum 25(OH)D And Offspring Outcomes In Pregnant Women

Objective To describe vitamin D level during pregnancy in Ma’anshan city and analyze risk factors of vitamin D levels during pregnancy. To explore the relationship of maternal vitamin D level and offspring outcomes.Methods 3272 mother–and–singleton–offspring pairs, in the 4 municipal hospital of Ma’anshan city between Nov 2008 and Oct 2010 for the fist visit, were selected into this prospective longitudinal study. The questionnaire included sociodemographic characters, body situation during pregnancy, life style and other information. Blood samples were extracted after consent. Blood samples were detected by liquid chromatography-tandem mass spectrometry(LC-MS/MS), the anthropometry data and birth outcome were copied from health care record. Using the chi-square test to analyze risk factors of vitamin D levels during pregnancy. The relationship of vitamin D concentration and birth outcomes were analyzed with univariate analysis by analysis of variance and chi-square test, and multivariate analysis by multiple linear regression and logistic regression analyses.Results The mean age of 3272 pregnant women was 26.68±3.50, and the median of vitamin D concentration was 25.75(6.50~91.25) nmol/L. There are 3143(96.1%) pregnant women with vitamin D concentration below 50nml/L, including 1544(47.5%) women below 25nmol/L. only 4(0.1%) women had adequate vitamin D(above 75 nml/L). The protective factors of high maternal vitamin D level are living in countryside, summer-autumn season, second and third trimester, non-vomiting of pregnancy, multi-vitamins, microelement, calcium and iron supplementation during first trimester,eating more rice, fresh vegetables, fresh fruit, pork, poultry, aquatic product, eggs, milk and animal giblets.Maternal vitamin D level is approximate positively related with neonatal chest circumference by using analysis of variance. Chi-square test shows a U-shaped relationship of maternal vitamin D and preterm birth. Multivariate analysis shows that subjects within the 3rd quintile of vitamin D levels had lower risk of preterm birth(OR=0.616, 95%CI: 0.406, 0.934) when compared with the lowest quintile. Subjects within the 2nd(OR=0.585, 95%CI: 0.362, 0.946) and 3rd(OR=0.564, 95%CI: 0.345, 0.923) quintile of vitamin D levels had lower risk of preterm birth when compared with the lowest quintile in early gestational, respectively. Subjects within the 3rd quintile of vitamin D levels had a 0.119 lower of Apgar-1 score when compared with the lowest quintile in second/third trimester.Conclusion Vitamin D deficiency is common among Maanshan pregnant women, supplement of maternal vitamin D and more eggs or milk that full of vitamin D are needed to improve maternal vitamin D levels. Maternal vitamin D level is related with neonatal chest circumference and preterm birth, neonatal chest circumference showed a trend of increase with higher maternal vitamin D, maternal with moderate vitamin D level had lowest risk of preterm birth, appropriate vitamin D nutritional status during pregnancy may can improve birth outcomes.