Trends and influencing factors of plasma folate levels in Chinese women at mid-pregnancy, late pregnancy and lactation periods

Folate status for women during early pregnancy has been investigated, but data for women during mid-pregnancy, late pregnancy or lactation are sparse or lacking. Between May and July 2014, we conducted a cross-sectional study in 1211 pregnant and lactating women from three representative regions in China. Approximately 135 women were enrolled in each stratum by physiological periods (mid-pregnancy, late pregnancy or lactation) and regions (south, central or north). Plasma folate concentrations were measured by microbiological assay. The adjusted medians of folate concentration decreased from 28 center dot 8 (interquartile range (IQR) 19 center dot 9, 38 center dot 2) nmol/l in mid-pregnancy to 18 center dot 6 (IQR 13 center dot 2, 26 center dot 4) nmol/l in late pregnancy, and to 17 center dot 0 (IQR 12 center dot 3, 22 center dot 5) nmol/l in lactation (P-for trend < 0 center dot 001). Overall, lower folate concentrations were more likely to be observed in women residing in the northern region, with younger age, higher pre-pregnancy BMI, lower education or multiparity, and in lactating women who had undergone a Caesarean delivery or who were breastfeeding exclusively. In total, 380 (31 center dot 4 %) women had a suboptimal folate status (folate concentration <13 center dot 5 nmol/l). Women in late pregnancy and lactating, residing in the northern region, having multiparity and low education level had a higher risk of suboptimal folate status, while those with older age had a lower risk. In conclusion, maternal plasma folate concentrations decreased as pregnancy progressed, and were influenced by geographic region and maternal socio-demographic characteristics. Future studies are warranted to assess the necessity of folic acid supplementation during later pregnancy and lactation especially for women at a higher risk of folate depletion.

Automated summary

The study found that as pregnancy progresses, maternal plasma folate concentrations decrease, influenced by geographic region and maternal demographic characteristics. Women in late pregnancy and lactating, residing in the northern region, having multiparity and low education level were at higher risk of suboptimal folate status, while older women had a lower risk. Further research is needed to assess the necessity of folic acid supplementation during later pregnancy and lactation, especially for high-risk women.