Institute of Reproductive and Child Health, Peking University/ Ministry of Health Key Laboratory of Reproductive Health; School of Public Health, Peking University, Beijing, China.
Birth Defects Res. 2017 Jul 17;109(13):1039-1047. doi: 10.1002/bdr2.1040. Epub 2017 Jun 1.
Optimal blood folate levels of women before pregnancy are critical to the prevention of neural tube defects (NTDs). However, few studies have focused on blood folate levels of women planning to become pregnant. The aims of this study were to assess plasma folate levels in women who planned to become pregnant in a population with high prevalence of NTDs, to identify factors associated with plasma folate levels, and to evaluate the risk of NTDs at the population level.
A total of 2065 women were enrolled at the time of premarital health check-up in two rural counties in northern China from November 2009 to December 2012. Fasting venous blood samples were collected and plasma folate concentrations were measured by microbiological method.
The overall median of plasma folate was 10.5 nmol/L. 50% of the women had a plasma folate level below 10.5 nmol/L, a cutoff for megaloblastic anemia, and 88% below 18 nmol/L, a proposed optimal plasma folate level for the prevention of NTDs. Folic acid supplementation was the only factor to be associated with plasma folate concentrations, but only 1.9% of the women reported having taken folic acid supplements. A population risk of 29.3 NTD cases per 10,000 births was predicted.
Women who planned to become pregnant had very low plasma folate in the population. Folic acid supplementation was the only factor to be associated with a high plasma folate concentration. High NTD risk would remain if women would get pregnant without having taken folic acid supplements. Birth Defects Research 109:1039-1047, 2017. © 2017 Wiley Periodicals, Inc.
孕妇在备孕前的最佳血液叶酸水平对于预防神经管缺陷（NTD）至关重要。然而，很少有研究关注计划怀孕的女性的血液叶酸水平。本研究的目的是评估高 NTD 流行地区计划怀孕女性的血浆叶酸水平，确定与血浆叶酸水平相关的因素，并评估人群 NTD 风险。
本研究于 2009 年 11 月至 2012 年 12 月在我国北方两个农村县进行婚前健康检查时，共纳入 2065 名女性。采集空腹静脉血样，采用微生物学法测量血浆叶酸浓度。
总体血浆叶酸中位数为 10.5nmol/L。50%的女性血浆叶酸水平低于 10.5nmol/L，这是巨幼细胞性贫血的界限，88%的女性血浆叶酸水平低于 18nmol/L，这是预防 NTD 的建议最佳血浆叶酸水平。叶酸补充是唯一与血浆叶酸浓度相关的因素，但仅有 1.9%的女性报告服用过叶酸补充剂。预测每 10000 例活产中 NTD 病例数为 29.3 例。
计划怀孕的女性血浆叶酸水平非常低。叶酸补充是唯一与高血浆叶酸浓度相关的因素。如果女性在没有服用叶酸补充剂的情况下怀孕，NTD 风险仍将很高。出生缺陷研究 109:1039-1047, 2017. © 2017 Wiley Periodicals, Inc.
