Table 2.
Association of maternal folic acid use with the risk of CHD.
| Maternal folic acid use | Control group (n = 617) |
Case group (n = 592) |
Univariable analysis | Unadjusted OR (95% CI) | Adjusted OR (95% CI)† |
|---|---|---|---|---|---|
| Use of folic acid for this pregnancy | |||||
| Yes | 574 (93.0%) | 507 (85.6%) | χ2 = 17.424, P = 0.000 | 1.00 (reference) | 1.00 (reference) |
| No | 43 (7.0%) | 85 (14.4%) | 2.24 (1.52–3.29) | 2.00 (1.3–42.98) | |
| Time of starting to use folic acid among women using folic acid | 2.17 (1.66–2.84) | 1.50 (1.08–2.09) | |||
| Three months prior to conception | 162 (28.4%) | 85 (16.8%) | χ2 = 37.514, P = 0.000 | 1.00 (reference) | 1.00 (reference) |
| First trimester of pregnancy | 403 (70.7%) | 393 (77.5%) | 1.86 (1.38–2.50) | 1.65 (1.22–2.23) | |
| Second trimester of pregnancy | 5 (0.9%) | 29 (5.7%) | 11.05(4.13–29.59) | 7.77 (2.52–23.96) | |
CHD, congenital heart disease; CI, confidence interval; OR, odds ratio.
†
Adjusted for gender, maternal age at pregnancy onset, education status, residence location, adverse pregnancy history (induced abortion or labor, fetal death or stillbirth, neonatal death, hypertension of pregnancy, gestational diabetes mellitus), family history (consanguineous marriages), maternal lifestyle before this pregnancy, harmful chemicals' exposure history in this pregnancy.