ICD-10-CM > O00-O9A > O30-O48 > O36 > O36.8 > O36.82 > O36.821 O36.821 Fetal anemia and thrombocytopenia, first trimester Non-Billable/Non-Specific Codes O36.8210..., not applicable or unspecifiedO36.8211..., fetus 1O36.8212..., fetus 2O36.8213..., fetus 3O36.8214..., fetus 4O36.8215..., fetus 5O36.8219..., other fetus