Table 3.
Folic acid supplementation and risk of heart defects and neural tube defects
| Variants of folic acid supplementation | Risk of heart defects | Risk of neural tube defects | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| No. of malformations | No. of infants | Incidence, per 1000 infants (95% CI) | Adjusted odds ratio (95% CI)a | P value | No. of malformations | No. of infants | Incidence, per 10,000 infants (95% CI) | Adjusted odds ratio (95% CI)a | P value | |
| Supplementation | ||||||||||
| No | 7 | 873 | 8.0 (2.1–13.9) | 1.00 | 1 | 867 | 11.5 (1.1–34.2) | 1.00 | ||
| Yes | 60 | 15,656 | 3.8 (2.9–4.8) | 0.47 (0.21–1.02) | 0.056 | 11 | 15,607 | 7.0 (2.9–11.2) | 0.64 (0.08–5.15) | 0.68 |
| Initiation | ||||||||||
| No supplementation | 7 | 873 | 8.0 (2.1–13.9) | 1.00 | 1 | 867 | 11.5 (1.1–34.2) | 1.00 | ||
| Earlier than 3 months before pregnancy | 10 | 1769 | 5.7 (2.2–9.2) | 0.80 (0.29–2.20) | 0.66 | 1 | 1760 | 5.7 (1.0–16.8) | 0.63 (0.03–11.69) | 0.76 |
| Within 3 months before pregnancy | 18 | 5039 | 3.6 (1.9–5.2) | 0.49 (0.20–1.21) | 0.12 | 7 | 5028 | 13.9 (3.6–24.2) | 1.62 (0.18–14.26) | 0.66 |
| After pregnancy | 31 | 8598 | 3.6 (2.3–4.9) | 0.45 (0.20–1.04) | 0.061 | 3 | 8570 | 3.5 (1.0–12.0) | 0.33 (0.03–3.22) | 0.34 |
| Duration | ||||||||||
| No supplement | 7 | 873 | 8.0 (2.1–13.9) | 1.00 | 1 | 867 | 11.5 (1.1–34.2) | 1.00 | ||
| ≤ 3 months | 41 | 10,526 | 3.9 (2.7–5.1) | 0.49 (0.22–1.10) | 0.084 | 6 | 10,491 | 5.7 (1.1–10.3) | 0.55 (0.07–4.69) | 0.59 |
| > 3 months | 18 | 4880 | 3.7 (2.0–5.4) | 0.50 (0.20–1.24) | 0.13 | 5 | 4867 | 10.0 (1.0–19.0) | 1.05 (0.11–10.19) | 0.97 |
aAdjusted for region, maternal age, ethnicity, parity, conception mode, education level, family income, history of adverse pregnancy outcomes, medicine exposure, and early pregnancy conditions