[Status of plasma folate in the third trimester of pregnant women and newborn babies in the northern rural areas of China].

OBJECTIVE

To study the plasma folate concentrations in the third trimester of pregnant women and newborn babies so as to assess the association between them.

METHODS

Pregnant women in Yuanshi and Laoting counties in Hebei province from May to June in 2009 were recruited with related information collected at enrollment. Those pregnant women being enrolled were followed up until delivery. Maternal blood was collected before delivery, and cord blood was collected after the expulsion of the placenta. Data from 437 pairs of women and newborns were analyzed. Plasma folate concentration was measured by Microbiological assay, with maternal plasma folate concentration < 6.8 nmol/L defined as folate deficiency. Neonatal plasma folate concentration below 10% was defined as relative deficiency. Student t-test and ANOVA were used to compare the plasma folate concentrations between the groups and χ(2) test was used to compare the situation of folate deficiency. In order to assess the association between maternal and newborn folate levels, logistic regression analysis was used to estimate the odds ratio of the neonatal plasma folate relative deficiency between the maternal folate deficient and normal groups after adjusting factors as age, BMI, region, career and education. Linear regression was used to test the trend by quintiles of maternal plasma folate concentration. Pearson's test was used to test the relationship between the ratio of neonatal and maternal plasma folate level and the level of maternal plasma folate.

RESULTS

The geometric mean of maternal plasma folate concentration was 8.0 (95%CI: 7.6 - 8.5) nmol/L and the deficiency was 29.3%, but in newborn babies, they were 24.0 (95%CI: 23.1 - 25.0) nmol/L and 0.9% respectively. The plasma folate level in newborn babies was 3.0 times as high as in maternal (t = 32.519, P < 0.01) but the neonatal plasma folate deficiency status was higher than in maternal (χ(2) = 137.2, P < 0.01). When compared with the normal plasma folate level group, the risk on neonatal plasma folate relative deficiency in the maternal folate deficiency group was significantly higher after adjusted for confounders (OR = 1.96, 95%CI: 1.02 - 3.80). The neonatal plasma folate level significantly increased along with the maternal plasma folate level (P(trend) < 0.05). The ratio of neonatal and maternal plasma folate level was significantly inversely correlated with the maternal folate level (r = -0.810, P < 0.001).

CONCLUSION

Folate status in newborns was much better than in their mothers', in the northern rural areas of China. The maternal folate status was positively correlated with their offspring's. Active placental transport for folate was significantly increasing when the maternal plasma folate level decreased.