ICD-10-CM > O00-O9A > O30-O48 > O36 > O36.2 > O36.23 O36.23 Maternal care for hydrops fetalis, third trimester Non-Billable/Non-Specific Codes O36.23X0..., not applicable or unspecifiedO36.23X1..., fetus 1O36.23X2..., fetus 2O36.23X3..., fetus 3O36.23X4..., fetus 4O36.23X5..., fetus 5O36.23X9..., other fetus