ICD-10-CM > O00-O9A > O20-O29 > O23 > O23.0 O23.0 Infections of kidney in pregnancy Non-Billable/Non-Specific Applicable To Pyelonephritis in pregnancy Codes O23.00Infections of kidney in pregnancy, unspecified trimesterO23.01Infections of kidney in pregnancy, first trimesterO23.02Infections of kidney in pregnancy, second trimesterO23.03Infections of kidney in pregnancy, third trimester