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Folic Acid Supplementation to Prevent Neural Tube Defects: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

M. Viswanathan, R. Urrutia, K. Hudson, J. Middleton, L. Kahwati

Journal of the American Medical Association (JAMA), 2023

990 participants · 63 citations

Abstract

Importance

Neural tube defects are among the most common birth defects in the US.

Objective

To review new evidence on the benefits and harms of folic acid supplementation for the prevention of neural tube defects to inform the US Preventive Services Task Force.

Evidence Review

Sources included PubMed, Cochrane Library, Embase, and trial registries from July 1, 2015, through July 2, 2021; references; and experts, with surveillance through February 10, 2023. Two investigators independently reviewed English-language randomized studies and nonrandomized cohort studies in very highly developed countries that focused on the use of folic acid supplementation for the prevention of neural tube defect-affected pregnancies; methodological quality was dually and independently assessed.

Findings

Twelve observational studies (reported in 13 publications) were eligible for this limited update (N = 1 244 072). Of these, 3 studies (n = 990 372) reported on the effect of folic acid supplementation on neural tube defects. For harms, 9 studies were eligible: 1 randomized clinical trial (n = 431) reported on variations in twin delivery, 7 observational studies (n = 761 125) reported on the incidence of autism spectrum disorder, and 1 observational study (n = 429 004) reported on maternal cancer. Two cohort studies and 1 case-control study newly identified in this update reported on the association between folic acid supplementation and neural tube defects (n = 990 372). One cohort study reported…

How strong is the evidence?

Evidence Hub reads this as a systematic review, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 990 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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