Evans D R
Br Med J. 1979 Apr 14;1(6169):975-6. doi: 10.1136/bmj.1.6169.975.
The overall incidence of anencephaly and spina bifida (ASB) in 69,056 pregnancies was 4.7/1000 births. ASB was more common (8.4/1000 births) among children of mothers who had had two or more abortions, but the increased risk was confined to spina bifida. A history of abortion was more common in older women and women of higher parity, but this was not matched by a similar increase in the incidence of ASB. The incidence of ASB was related to social class, but the prevalence of previous abortions was similar in all classes. The results suggest that expectant mothers with a history of two or more abortions have an increased risk of producing a child with spina bifida. The abortions are considered to be a manifestation of previous abnormal conceptions rather than the primary cause.
在69056例妊娠中，无脑儿和脊柱裂（ASB）的总体发病率为4.7/1000活产。在有两次或更多次流产史的母亲所生子女中，ASB更为常见（8.4/1000活产），但增加的风险仅限于脊柱裂。流产史在年龄较大和多产妇女中更为常见，但ASB发病率并未相应增加。ASB的发病率与社会阶层有关，但既往流产的发生率在所有阶层中相似。结果表明，有两次或更多次流产史的孕妇生出脊柱裂患儿的风险增加。流产被认为是既往异常妊娠的一种表现，而非主要原因。
