ICD-10-CM > O00-O9A > O30-O48 > O30 > O30.0 > O30.02 O30.02 Conjoined twin pregnancy Non-Billable/Non-Specific Codes O30.021Conjoined twin pregnancy, first trimesterO30.022Conjoined twin pregnancy, second trimesterO30.023Conjoined twin pregnancy, third trimesterO30.029Conjoined twin pregnancy, unspecified trimester