MMWR Morb Mortal Wkly Rep. 2010 Aug 13;59(31):980-4.
Neural tube defects (NTDs) are serious birth defects that result from the failure of the neural tube to close in the cranial region (anencephaly) or more caudally along the spine (spina bifida) by the 28th day of gestation. Infants born with anencephaly usually die within a few days of birth, and those with spina bifida have life-long disabilities with varying degrees of paralysis. Currently, identified risk factors for NTDs include a mother who previously had an NTD-affected pregnancy, maternal diabetes, obesity, hyperthermia, certain antiseizure medications, genetic variants, race/ethnicity, and nutrition (particularly folic acid insufficiency). In the United States, during 1995-1996, approximately 4,000 pregnancies were affected by an NTD. This number declined to 3,000 pregnancies in 1999-2000 after fortification of enriched cereal grain products with folic acid was mandated. Worldwide, in 1998, approximately 300,000 births were affected by an NTD.
神经管缺陷（NTDs）是一种严重的出生缺陷，是由于妊娠第 28 天颅部的神经管未能闭合（无脑畸形）或更靠尾部沿脊柱闭合（脊柱裂）所致。患有无脑畸形的婴儿通常在出生后几天内死亡，而患有脊柱裂的婴儿则会终身残疾，其瘫痪程度也各不相同。目前，已确定的神经管缺陷风险因素包括：曾患有神经管缺陷妊娠的母亲、母亲糖尿病、肥胖、发热、某些抗癫痫药物、遗传变异、种族/民族和营养（尤其是叶酸不足）。在美国，1995-1996 年期间，约有 4000 例妊娠受到神经管缺陷的影响。1999-2000 年强化富含叶酸的谷物产品后，这一数字降至 3000 例。1998 年，全世界约有 30 万例出生受到神经管缺陷的影响。
