ICD-10-CM > O00-O9A > O30-O48 > O36 > O36.0 > O36.09 > O36.099 O36.099 Maternal care for other rhesus isoimmunization, unspecified trimester Non-Billable/Non-Specific Codes O36.0990..., not applicable or unspecifiedO36.0991..., fetus 1O36.0992..., fetus 2O36.0993..., fetus 3O36.0994..., fetus 4O36.0995..., fetus 5O36.0999..., other fetus