title: Acute antepartum pyelonephritis in pregnancy: a critical analysis of risk factors and outcomes.
abstract: OBJECTIVE
  To test the incidence and sonographic parameters of pyelonephritis during pregnancy, and to examine risk factors and pregnancy outcomes of women with acute antepartum pyelonephritis.
  
  
  METHODS
  A retrospective population-based study comparing all singleton pregnancies of patients with and without acute antepartum pyelonephritis was performed. Patients lacking prenatal care as well as multiple gestations were excluded from the study. Multiple logistic regression models were used to control for confounders.
  
  
  RESULTS
  Out of 219,612 singleton deliveries in 1988-2010, 165 women (0.07%) suffered from acute antepartum pyelonephritis. Abnormal sonographic findings were found in 85.7% of the patients with pyelonephritis. Pyelonephritis was significantly associated with nulliparity (46.1% vs. 24.4%, p<0.001), younger maternal age (26.3 ± 6.0 vs. 28.6 ± 5.8 years, p<0.001), intrauterine growth restriction (IUGR) (6.7% vs. 2.1%, p<0.001), placental abruption (3.6% vs. 0.7%, p<0.001), low 1 min Apgar scores (10.3% vs. 6.0%, p<0.05), urinary tract infection (UTI) (4.2% vs. 0.4%, p<0.001) and preterm delivery (less than 37 weeks gestation; 20.0% vs. 7.8%; p<0.001). Using a multivariable analysis, independent risk factors for acute antepartum pyelonephritis were nulliparity (OR 2.0; 95% C.I 1.4-2.9; p<0.001), UTI (OR 10.3; 95% C.I 4.8-22.1; p<0.001) and younger maternal age (OR 0.96; 95% C.I 0.93-0.99; p=0.009). Using another multivariable analysis, with preterm delivery as the outcome variable, acute antepartum pyelonephritis was found as an independent risk factor for preterm delivery (OR 2.6; 95% C.I 1.7-3.9; p<0.001).
  
  
  CONCLUSIONS
  Acute antepartum pyelonephritis is associated with adverse perinatal outcomes and specifically is an independent risk factor for preterm delivery.
authors.affiliation: Department of Diagnostic Radiology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
authors.forename: Evelina
authors.initials: E
authors.lastname: Farkash
authors.forename: Adi Y
authors.initials: AY
authors.lastname: Weintraub
authors.forename: Ruslan
authors.initials: R
authors.lastname: Sergienko
authors.forename: Arnon
authors.initials: A
authors.lastname: Wiznitzer
authors.forename: Alex
authors.initials: A
authors.lastname: Zlotnik
authors.forename: Eyal
authors.initials: E
authors.lastname: Sheiner
mesh_terms: D000037:Abruptio Placentae / Q000000981:diagnostic imaging / Q000453:epidemiology; D000328:Adult; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011256:Pregnancy Outcome; D011704:Pyelonephritis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014463:Ultrasonography