| Value | Category |
|---|---|
| 0 | |
| 1 | 1st month of pregnancy |
| 2 | 2nd month of pregnancy |
| 3 | 3rd month of pregnancy |
| 4 | 4th month of pregnancy |
| 5 | 5th month of pregnancy |
| 6 | 6th month of pregnancy |
| 7 | 7th month of pregnancy |
| 8 | 8th month of pregnancy |
| 9 | 9th month of pregnancy |
| 77 | Inap |
| 88 | Do not know |
| 99 | No response |