| Variable | Sildenafil plus low-dose aspirin (n = 200) | Low-dose aspirin only (n = 200) | P-value* | ||
| n | % | N | % | ||
| Early PE | 6 | 3.0% | 6 | 3.0% | 1.000 |
| Severe PE | 7 | 3.5% | 8 | 4.0% | 0.792 |
| Gestational hypertension | 20 | 10.0% | 16 | 8.0% | 0.485 |
| APH | 6 | 3.0% | 5 | 2.5% | 0.760 |
| Withdrawal from study | 5 | 2.5% | 3 | 1.5% | 0.724§ |
| Loss to follow-up | 10 | 5.0% | 7 | 3.5% | 0.457 |