ICD-10-CM > O00-O9A > O30-O48 > O36 > O36.5 > O36.59 > O36.599 O36.599 Maternal care for other known or suspected poor fetal growth, unspecified trimester Non-Billable/Non-Specific Codes O36.5990..., not applicable or unspecifiedO36.5991..., fetus 1O36.5992..., fetus 2O36.5993..., fetus 3O36.5994..., fetus 4O36.5995..., fetus 5O36.5999..., other fetus