ICD-10-CM > O00-O9A > O20-O29 > O24 > O24.9 > O24.91 O24.91 Unspecified diabetes mellitus in pregnancy Non-Billable/Non-Specific Codes O24.911Unspecified diabetes mellitus in pregnancy, first trimesterO24.912Unspecified diabetes mellitus in pregnancy, second trimesterO24.913Unspecified diabetes mellitus in pregnancy, third trimesterO24.919Unspecified diabetes mellitus in pregnancy, unspecified trimester