Comparison of mothers who purchased at least once or did not purchase FA within year before birth of each child, by parity
| Parity | No purchases (N=107 278) (n (%)) | At least one purchase (N=470 926) (n (%)) | P value |
| Nulliparous | 33 731 (14.2) | 202 999 (85.8) | <0.01 |
| 1 | 37 624 (20.0) | 150 762 (80.0) | |
| 2 | 20 377 (22.3) | 71 090 (77.7) | |
| ≥3 | 15 546 (25.2) | 46 075 (74.8) |
FA, folic acid.