ICD-10-CM > O00-O9A > O30-O48 > O31 > O31.8 > O31.8X O31.8X Other complications specific to multiple gestation Non-Billable/Non-Specific Codes O31.8X1Other complications specific to multiple gestation, first trimesterO31.8X10..., not applicable or unspecifiedO31.8X11..., fetus 1O31.8X12..., fetus 2O31.8X13..., fetus 3O31.8X14..., fetus 4O31.8X15..., fetus 5O31.8X19..., other fetusO31.8X2Other complications specific to multiple gestation, second trimesterO31.8X20..., not applicable or unspecifiedO31.8X21..., fetus 1O31.8X22..., fetus 2O31.8X23..., fetus 3O31.8X24..., fetus 4O31.8X25..., fetus 5O31.8X29..., other fetusO31.8X3Other complications specific to multiple gestation, third trimesterO31.8X30..., not applicable or unspecifiedO31.8X31..., fetus 1O31.8X32..., fetus 2O31.8X33..., fetus 3O31.8X34..., fetus 4O31.8X35..., fetus 5O31.8X39..., other fetusO31.8X9Other complications specific to multiple gestation, unspecified trimesterO31.8X90..., not applicable or unspecifiedO31.8X91..., fetus 1O31.8X92..., fetus 2O31.8X93..., fetus 3O31.8X94..., fetus 4O31.8X95..., fetus 5O31.8X99..., other fetus