Acute pyelonephritis is a serious infection in pregnancy. It is presented with fever, shaking chills and flank pain. Intravenous hydration and antimicrobial therapy are sufficient in the treatment unless pyelonephritis is complicated. In case of fever persisting for more than 48 h despite appropriate antimicrobial treatment, a possible complication such as urinary tract obstruction, abscess or phlegmon should be considered. Here, we present an 18-year-old pregnant woman with acute pyelonephritis whose persistent fever returned to normal after double-J ureteral stent was placed even if she had no finding of such a complication.