Maternal care for abnormalities of the fetal heart rate or rhythm, second trimester, other fetus

O36.8329 (“Maternal care for abnormalities of the fetal heart rate or rhythm, second trimester, other fetus”) is a diagnosis code that identifies a specific condition, injury, or finding on a medical claim in the ICD-10-CM code set. Whether it is billed — and whether a payer covers it — depends on the clinical setting, documentation, and plan rules.