| Variables | Serum β-HCG concentration | df | χ2 | p value | |
| Age | <5 IU/L (Normal) | >5 IU/L (Elevated) | 3 | 8.24 | 0.041 |
| 18 - 23 | 12 | 0 |
|
|
|
| 24 - 29 | 71 | 2 |
|
|
|
| 30 - 35 | 111 | 7 |
|
|
|
| 36 - 40 | 17 | 4 |
|
|
|
| Parity |
|
| 2 | 62.96 | <0.001* |
| Nullipara | 12 | 9 |
|
|
|
| Primipara | 24 | 3 |
|
|
|
| Multipara | 175 | 1 |
|
|
|