| O36.8310 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified | BILLABLE CODE |
| O36.8311 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, fetus 1 | BILLABLE CODE |
| O36.8312 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, fetus 2 | BILLABLE CODE |
| O36.8313 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, fetus 3 | BILLABLE CODE |
| O36.8314 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, fetus 4 | BILLABLE CODE |
| O36.8315 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, fetus 5 | BILLABLE CODE |
| O36.8319 | Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, other fetus | BILLABLE CODE |
