Impact of trimester on morbidity of acute pyelonephritis in pregnancy

We sought to compare maternal and neonatal morbidity as well as obstetric outcomes associated with pyelonephritis in pregnancy during the first compared to the second/third trimester.

A retrospective cohort analysis was performed of all pregnant women admitted to a single tertiary care hospital between January 2004 and June 2007 with pyelonephritis. The primary outcome was length of hospitalization. The study had 80% power to detect a 1-day difference in length of stay.

In all, 219 cases of acute pyelonephritis were identified: 23 diagnosed in the first trimester and 196 in the second/third trimester. Women were hospitalized for a median of 4 days in both the first (range, 2-7) and second/third (range, 2-9; P = .6) trimesters. Neonatal and obstetric outcomes were not statistically significant.

Maternal morbidity and obstetric outcomes do not differ between first- and second-/third-trimester pyelonephritis. First-trimester pyelonephritis should be aggressively treated to prevent adverse outcomes.