1985～1987年在北京地区进行了孕产妇血清叶酸分布特点及与胎儿神经管缺损关系的研究,结果显示:正常孕妇血清叶酸水平随孕周增加逐渐下降,且冬季最低,秋季最高,农村低浓度叶酸所占比重远高于城市。44例神经管缺损儿母亲的血清叶酸略低于88例正常儿对照母亲。病例对照研究结果表明,母亲血清叶酸水平低下,极少食水果、膳食质量差和女性胎儿可能是胎儿发生神经管缺损的危险因子。 From 1985 to 1987, the study on the relationship between serum folic acid distribution and fetal neural tube defects in Beijing area showed that the level of serum folic acid in normal pregnant women decreased gradually with the increase of gestational age, the lowest in winter and the highest in autumn, the lowest in rural areas The proportion of folic acid is much higher than the city. Forty-four children with neural tube defects had slightly lower serum folate levels than the 88 normal mothers. Case-control studies have shown that maternal serum folic acid levels are low, eat less fruits, poor quality of diet and female fetuses may be fetal risk factors for neural tube defects.