ICD-10-CM > O00-O9A > O30-O48 > O36 > O36.8 > O36.83 > O36.832 O36.832 Maternal care for abnormalities of the fetal heart rate or rhythm, second trimester Non-Billable/Non-Specific Codes O36.8320..., not applicable or unspecifiedO36.8321..., fetus 1O36.8322..., fetus 2O36.8323..., fetus 3O36.8324..., fetus 4O36.8325..., fetus 5O36.8329..., other fetus