ICD-10-CM > O00-O9A > O30-O48 > O41 > O41.1 > O41.12 O41.12 Chorioamnionitis Non-Billable/Non-Specific Codes O41.121Chorioamnionitis, first trimesterO41.1210..., not applicable or unspecifiedO41.1211..., fetus 1O41.1212..., fetus 2O41.1213..., fetus 3O41.1214..., fetus 4O41.1215..., fetus 5O41.1219..., other fetusO41.122Chorioamnionitis, second trimesterO41.1220..., not applicable or unspecifiedO41.1221..., fetus 1O41.1222..., fetus 2O41.1223..., fetus 3O41.1224..., fetus 4O41.1225..., fetus 5O41.1229..., other fetusO41.123Chorioamnionitis, third trimesterO41.1230..., not applicable or unspecifiedO41.1231..., fetus 1O41.1232..., fetus 2O41.1233..., fetus 3O41.1234..., fetus 4O41.1235..., fetus 5O41.1239..., other fetusO41.129Chorioamnionitis, unspecified trimesterO41.1290..., not applicable or unspecifiedO41.1291..., fetus 1O41.1292..., fetus 2O41.1293..., fetus 3O41.1294..., fetus 4O41.1295..., fetus 5O41.1299..., other fetus