Table 2 Post-conception folic acid supplementation and risk of congenital malformations
From: Initiation and duration of folic acid supplementation in preventing congenital malformations
Variants of folic acid supplementation | Risk of congenital malformations | ||||
|---|---|---|---|---|---|
No. of malformations | No. of infants | Prevalence,% (95% CI) | Adjusted odds ratio (95% CI)a | P value | |
Supplementation | |||||
 No | 21 | 887 | 2.37 (1.37–3.37) | 1.00 |  |
 Yes | 128 | 8695 | 1.47 (1.22–1.73) | 0.64 (0.40–1.03) | 0.063 |
Initiation | |||||
 No supplement | 21 | 887 | 2.37 (1.37–3.37) | 1.00 |  |
 The first month | 57 | 4430 | 1.29 (0.95–1.62) | 0.55 (0.33–0.91) | 0.02 |
 The second month | 51 | 3343 | 1.53 (1.11–1.94) | 0.64 (0.38–1.07) | 0.086 |
 The third month | 20 | 922 | 2.17 (1.23–3.11) | 0.91 (0.49–1.70) | 0.77 |
Duration | |||||
 No supplement | 21 | 887 | 2.37 (1.37–3.37) | 1.00 |  |
 1 month | 33 | 1993 | 1.66 (1.10–2.22) | 0.68 (0.39–1.19) | 0.17 |
 1.01 months ~  | 63 | 4572 | 1.38 (1.04–1.72) | 0.59 (0.36–0.98) | 0.041 |
 2.01 months ~  | 32 | 2130 | 1.50 (0.99–2.02) | 0.66 (0.38–1.17) | 0.15 |