ICD-10-CM > O00-O9A > O30-O48 > O31 > O31.8 > O31.8X > O31.8X1 O31.8X1 Other complications specific to multiple gestation, first trimester Non-Billable/Non-Specific Codes O31.8X10..., not applicable or unspecifiedO31.8X11..., fetus 1O31.8X12..., fetus 2O31.8X13..., fetus 3O31.8X14..., fetus 4O31.8X15..., fetus 5O31.8X19..., other fetus