Nonlinear Relationship Between Maternal and Cord Blood Vitamin B12 and Folate from a Chinese Population-Based Study

Abstract

Yujiao Du,1 Jing Li,1 Pengfei Qu,2 Shaonong Dang1 1Department of Epidemiology and Biostatistics, School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, 710061, People’s Republic of China; 2Assisted Reproduction Center, Northwest Women’s and Children’s Hospital, Xi’an Jiaotong University Health Science Center, Xi’an, 710003, People’s Republic of ChinaCorrespondence: Shaonong Dang, Department of Epidemiology and Biostatistics, School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, 710061, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: There remains a data gap on vitamin B12 and folate level in maternal and child populations. This study aimed to assess the status of vitamin B12 and folate in maternal serum (MS) and umbilical cord serum (UCS).Materials and Methods: This was a planned secondary analysis of a case-control study. A total of 858 pregnant women during late pregnancy and their newborns in the hospitals of China were included. Maternal peripheral venous blood and neonatal umbilical cord blood were collected to determine serum vitamin B12 and folate concentration. Relationship of vitamin B12 or folate concentration between MS and UCS was assessed by a quantile regression model and the non-linear relationship between them was examined.Results: Nutritional status of serum folate was better than that of vitamin B12. Prevalence of deficiency in MS vitamin B12 and folate was 73.4% and 14.2%, respectively and these figures were about 17.8% and 0.1% in UCS. Both vitamin B12 and folate levels in UCS were significantly higher than those in MS (vitamin B12: 321.0 pg/mL vs 158.3 pg/mL, folate: 16.5 ng/mL vs 7.0 ng/mL, P < 0.001). The median UCS-MS ratio of vitamin B12 and folate was 2.0 (95% CI: 1.94– 2.06) and 2.4 (95% CI: 2.30– 2.53), respectively. The levels of folate and vitamin B12 in UCS increased nonlinearly with their increase in MS which presented an inverted U-shaped curve.Conclusion: Deficiency in vitamin B12 and folate in the women during late pregnancy in China is prevalent. Nutritional status of the two vitamins in umbilical cord serum is correlated nonlinearly with that in maternal serum. Folic acid supplementation may be accompanied with vitamin B12 to improve status of vitamin B12 and folate during pregnancy.Keywords: vitamin B12, folate, umbilical cord serum, maternal serum, pregnancy

Keywords

• vitamin b12；folate；umbilical cord serum；maternal serum；pregnancy