CMAJ. 1994 Jul 15;151(2):159-66.
To make recommendations on nutritional interventions and screening manoeuvres to prevent the birth of infants with neural tube defects (NTDs).
Folic acid consumption through diet or supplementation in women at low risk and at high risk of having a fetus with an NTD, and maternal serum alpha-fetoprotein (MSAFP) screening in low-risk pregnancies.
A reduction in the incidence rate of NTDs and potentially harmful effects of false-positive results of screening tests (i.e., abortion of a normal fetus).
A MEDLINE search with the use of medical subject headings "neural tube defects," "prenatal diagnosis" and "prevention and control" identified 103 original articles published between January 1979 and March 1993. Two reviewers extracted the data by applying the rules of evidence developed by the Canadian Task Force on the Periodic Health Examination.
The task force's evidence-based methods and values were used; high value was placed on prevention of NTDs and on limitation of the harmful effects of a pregnancy involving a fetus with an NTD.
BENEFITS, HARMS AND COSTS: Evidence suggests that folic acid supplementation can decrease the incidence rate of NTDs in low-risk pregnancies by 40% to 60% with no adverse effects. MSAFP screening between the 16th and 18th weeks of gestation can reach a sensitivity of 83% and a specificity of 98% when it is used as part of an organized program. The effect of screening on the incidence rate of NTDs depends on whether affected fetuses are aborted.
All women of childbearing age should be advised to increase their consumption of folic acid through diet or supplementation to 0.4 mg/d beginning 1 month before pregnancy and ending at the start of the second trimester. MSAFP screening is recommended in low-risk pregnancies only when it is part of a screening program that includes access to all necessary diagnostic services. High-risk women should be referred to genetic counselling before they plan a pregnancy.
These recommendations are comparable to the current recommendations of the US Centers for Disease Control and Prevention, the Society of Obstetricians and Gynaecologists of Canada, the Canadian Laboratory Centre for Disease Control and the Canadian College of Medical Geneticists, and they were validated through external review.
These guidelines were developed and endorsed by the Canadian task force, which funded by Health Canada.
就营养干预措施及筛查手段提出建议，以预防神经管缺陷（NTD）婴儿的出生。
低风险及高风险胎儿患NTD的女性通过饮食或补充剂摄入叶酸，以及对低风险妊娠进行母血清甲胎蛋白（MSAFP）筛查。
降低NTD的发病率以及筛查试验假阳性结果的潜在有害影响（即正常胎儿流产）。
使用医学主题词“神经管缺陷”、“产前诊断”和“预防与控制”在MEDLINE数据库进行检索，共识别出1979年1月至1993年3月期间发表的103篇原创文章。两名评审员根据加拿大定期健康检查特别工作组制定的证据规则提取数据。
采用了特别工作组基于证据的方法和价值观；高度重视预防NTD以及限制涉及患NTD胎儿的妊娠的有害影响。
益处、危害及成本：有证据表明，补充叶酸可使低风险妊娠中NTD的发病率降低40%至60%，且无不良影响。妊娠第16至18周进行MSAFP筛查，作为有组织项目的一部分使用时，敏感性可达83%，特异性可达98%。筛查对NTD发病率的影响取决于受影响胎儿是否流产。
应建议所有育龄妇女在怀孕前1个月开始至孕中期开始时，通过饮食或补充剂将叶酸摄入量增加至0.4mg/天。仅当MSAFP筛查作为包括所有必要诊断服务的筛查项目的一部分时，才建议在低风险妊娠中进行。高风险女性在计划怀孕前应转诊至遗传咨询门诊。
这些建议与美国疾病控制与预防中心、加拿大妇产科学会、加拿大疾病控制实验室中心及加拿大医学遗传学家学会的当前建议相当，并通过外部评审得到验证。
这些指南由加拿大特别工作组制定并认可，该工作组由加拿大卫生部资助。
