Calgary, AB.
Toronto, ON.
J Obstet Gynaecol Can. 2022 Jun;44(6):707-719.e1. doi: 10.1016/j.jogc.2022.04.004.
To provide updated guidance on pre-conception folic acid and multivitamin supplementation for primary and secondary (recurrence) prevention of neural tube defects and other folate-sensitive congenital anomalies.
Women aged 12-45 years who could become pregnant should be aware of the risk of serious birth defects without adequate pre-conception and first-trimester folic acid supplementation.
Optimizing folic acid supplementation is complex and depends on factors including dosage; type of supplement; bioavailability of folate from food, timing of initiating supplementation; and metabolic and genetic factors. For all women who could become pregnant, a low daily dosage of folic acid is recommended before conception and throughout pregnancy and breastfeeding. High-dosage folic acid supplementation is recommended only for women who can become pregnant and have had a previous pregnancy affected by a neural tube defect or other folate-sensitive congenital anomaly. Directed personalized approaches could be considered and adopted for women who can become pregnant and have complex risks (genetic, medical, or surgical risk factors), using new knowledge of co-factor metabolism and synergy, as well as red blood cell or serum folate testing. Such approaches would require changes to current provincial health care maternal serum folate screening/testing.
New approaches to oral folic acid supplementation, including triage tools, need to be considered to optimize the benefits of decreasing risk of neural tube defects and folate-sensitive congenital anomalies.
BENEFITS, HARMS, AND COSTS: Oral folic acid supplementation, or dietary folate intake combined with a multivitamin/micronutrient supplement, is associated with lower rates of neural tube defects, other folate-sensitive birth defects, and obstetrical complications. The costs are those attributable to daily vitamin supplementation and a healthy, folate-rich diet.
A literature search was designed and carried in PubMed and the Cochrane Library databases from 1990 to 2021 using following MeSH terms and keywords (and variants): folic acid supplementation; folate food fortification; primary neural tube defect prevention; prevention of recurrence of neural tube defects; folate-sensitive birth defects; folate supplementation benefit; folate supplementation risk; folate pregnant woman physiology; pregnant woman RBC folate level; pregnant woman serum folate levels; folate and epilepsy; folate and obesity. This guideline was based upon expert guidelines or opinions, systematic reviews, randomized controlled clinical trials, and observational case-control studies and case series retrieved, published in English from 1990 to 2021.
The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).
Maternity health care providers (physicians, midwives, nurses) and other providers of pregnancy-related wellness and health counselling.
RECOMMENDATIONS.
为预防神经管缺陷和其他叶酸敏感先天畸形的一级（初次）和二级（复发）预防，提供关于受孕前叶酸和多种维生素补充的最新指导。
12-45 岁有生育能力的妇女应了解严重出生缺陷的风险，因为她们可能没有足够的受孕前和孕早期叶酸补充。
优化叶酸补充是复杂的，取决于剂量、补充剂类型、食物中叶酸的生物利用度、补充起始时间、代谢和遗传因素等因素。对于所有有生育能力的妇女，建议在受孕前和整个孕期及哺乳期服用低剂量叶酸。高剂量叶酸补充仅适用于有生育能力且曾有过神经管缺陷或其他叶酸敏感先天畸形妊娠的妇女。对于有生育能力且存在复杂风险（遗传、医疗或手术危险因素）的妇女，可以考虑并采用针对性的个体化方法，利用新的共因子代谢和协同作用知识，以及红细胞或血清叶酸检测。这些方法需要改变当前省级医疗保健母体血清叶酸筛查/检测。
需要考虑新的口服叶酸补充方法，包括分诊工具，以优化降低神经管缺陷和叶酸敏感先天畸形风险的益处。
益处、危害和成本：口服叶酸补充或饮食叶酸摄入与多种维生素/微量营养素补充相结合，可降低神经管缺陷、其他叶酸敏感先天缺陷和产科并发症的发生率。成本归因于每日维生素补充和健康、富含叶酸的饮食。
在 PubMed 和 Cochrane 图书馆数据库中，使用以下 MeSH 术语和关键字（及其变体）进行了文献检索和设计：叶酸补充；叶酸食物强化；一级神经管缺陷预防；预防神经管缺陷复发；叶酸敏感先天缺陷；叶酸补充益处；叶酸补充风险；孕妇叶酸生理学；孕妇红细胞叶酸水平；孕妇血清叶酸水平；叶酸与癫痫；叶酸与肥胖。本指南基于专家指南或意见、系统评价、随机对照临床试验和观察性病例对照研究和病例系列研究，检索并发表于 1990 年至 2021 年的英文文献。
作者使用推荐评估、制定与评价（GRADE）方法对证据质量和建议强度进行了评级。请参见在线附录 A（表 A1 用于定义，表 A2 用于强推荐和弱推荐的解释）。
产妇保健提供者（医生、助产士、护士）和其他提供妊娠相关健康和保健咨询的人员。
建议。
