| 妊娠阶段 | IDA [n (%)] | ID [n (%)] |
| 孕早期(n = 21) | 0 (0) | 3 (14.3) |
| 孕中期(n = 49) | 8 (16.3)* | 22 (44.9)* |
| 孕晚期(n = 259) | 49 (18.9)* | 163 (62.9)* |
| χ2 | 4.894 | 22.297 |
| P | 0.087 | 0.000 |