ICD-10-CM > O00-O9A > O30-O48 > O30 > O30.0 > O30.03 O30.03 Twin pregnancy, monochorionic/diamniotic Non-Billable/Non-Specific Applicable To Twin pregnancy, one placenta, two amniotic sacs Codes O30.031Twin pregnancy, monochorionic/diamniotic, first trimesterO30.032Twin pregnancy, monochorionic/diamniotic, second trimesterO30.033Twin pregnancy, monochorionic/diamniotic, third trimesterO30.039Twin pregnancy, monochorionic/diamniotic, unspecified trimester