无脑儿、脊柱裂和脑积水等神经管缺损畸形是常见的胎儿畸形。出生过一胎神经管缺损儿的母亲,以后胎次中此类畸形的发生率可增高至5％,有过两胎神经管缺损儿者,以后胎次中该种发生率可再增高至10％。为了降低先天性畸形的发生率、出生健康胎儿,就要有一种能预测胎儿畸形,对有危险的孕妇进行鉴定,早期作出诊断并及时终止妊娠的方法。近年来国内外作者报道,存在上述畸形 No brain children, spina bifida and hydrocephalus neural tube defects such as malformations are common fetal abnormalities. The birth of a fetus with neural tube defects in the mother, the future parity of such deformities can be increased to 5%, there are two fetal neural tube defects in children after the parity of the kind of incidence can be increased to 10 %. In order to reduce the incidence of congenital malformations, birth healthy fetus, we must have a predictable fetal malformations, identification of pregnant women at risk, early diagnosis and timely termination of pregnancy method. In recent years, domestic and foreign authors reported the existence of the above deformity