A randomised trial of low dose folic acid to prevent neural tube defects. The Irish Vitamin Study Group.

Study answer

What this study found

The folic acid-containing regimens showed the most favorable pattern, with no neural tube defect recurrences reported in the folic acid groups. Among informative pregnancies, there was no recurrence in the 85 infants/fetuses in the folic acid-only group, while there was 1 recurrence in the 89 infants/fetuses in the multivitamin-only group; the report also states no recurrence among the 172 infants/fetuses in the two folic acid groups combined. Compared with non-randomized controls, the folic acid groups had a statistically significant lower recurrence rate, but the authors cautioned about…

Study & population

Randomized, block-randomized, stratified trial in women with a previous pregnancy affected by a neural tube defect who were planning or entering a subsequent pregnancy at 12 Irish hospitals.

Intervention

Women were assigned to one of three oral tablet regimens taken three times daily for at least two months before conception and until the third missed period: folic acid alone, multivitamins without folic acid, or folic acid plus multivitamins.

Key limitation

Small numbers of outcome events limited precision and made between-group comparisons unstable.

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Original abstract