| Value | Category | Cases | |
|---|---|---|---|
| 1 | Ultrasound | 89 |
25.5%
|
| 2 | By uterine size on bimanual exam | 28 |
8%
|
| 3 | LMP (last menstrual period) | 228 |
65.3%
|
| 98 | Unknown/missing | 4 |
1.1%
|
| Sysmiss | 55 |