ICD-10-CM > O00-O9A > O30-O48 > O31 > O31.8 > O31.8X > O31.8X2 O31.8X2 Other complications specific to multiple gestation, second trimester Non-Billable/Non-Specific Codes O31.8X20..., not applicable or unspecifiedO31.8X21..., fetus 1O31.8X22..., fetus 2O31.8X23..., fetus 3O31.8X24..., fetus 4O31.8X25..., fetus 5O31.8X29..., other fetus