Table 3. Description of folic acid supplement for the first and second pregnancy (among those taking folic acid).
| Folic acid (FA) supplement | First NTDs (N=233) | Second pregnancy (N=455) | Recurrent NTDs (N=7) | Second pregnancy without NTDs (N=449) | P* |
|---|---|---|---|---|---|
| Period of FA supplementation | 0.770 | ||||
| 3 months before pregnancy | 31(13.3) | 218(37.7) | 3(43.0) | 215(37.9) | |
| 2 months before pregnancy | 7(3.0) | 27(4.7) | 0 | 27(4.8) | |
| 1 month before pregnancy | 25(10.7) | 31(5.4) | 0 | 31(5.5) | |
| After pregnancy | 170(73.0) | 179(31.0) | 4(57.0) | 175(30.8) | |
| Missing | 0 | 123(21.3) | 0 | 120(21.1) | |
| FA supplements dose | 0.722 | ||||
| 0.4 mg | 331(57.3) | 4(57.0) | 327(57.6) | ||
| 0.8 mg | 36(6.2) | 1(14.0) | 35(6.2) | ||
| 1-3 mg | 6(1.0) | 0 | 6(1.1) | ||
| ≥4 mg | 69(11.9) | 1(14.0) | 68(12.0) | ||
| Missing | 136(23.5) | 1(14.0) | 132(23.2) | ||
* Compared between recurrent NTDs and the second pregnancy without NTDs