Objective. Pyelonephritis is a common infectious morbidity of pregnancy. Though anemia is commonly associated with pyelonephritis, there are little data describing the effect of pyelonephritis with anemia on pregnancy outcomes. The purpose of this study was to further assess the association of anemia with infectious morbidity and pregnancy complications among women with pyelonephritis. Study Design. We conducted a retrospective cohort study of pregnant women admitted to Duke University Hospital between July 2006 and May 2012 with pyelonephritis. Demographic, laboratory, and clinical data from the subject’s pregnancy and hospitalizations were analyzed. Patients with pyelonephritis and anemia (a hematocrit < 32) were compared to those without anemia. Descriptive statistics were used to compare the two groups. Results. 114 pregnant women were admitted with pyelonephritis and 45 (39.5%) had anemia on admission. There was no significant difference in age, race, preexisting medical conditions, or urine bacterial species between patients with anemia and those without. Women with anemia were more likely to deliver preterm (OR 3.3 (95% CI 1.07, 11.4), ). When controlling for race and history of preterm delivery, women with anemia continued to have increased odds of preterm birth (OR 6.0, CI 1.4, 35, ). Conclusion. Women with pyelonephritis and anemia are at increased risk for preterm delivery. 1. Introduction Pyelonephritis is the most common nonobstetric indication for antepartum admissions. Upper urinary tract infection complicates 1%-2% of pregnancies and has the potential to cause severe maternal and fetal morbidity [1–3]. The physiologic changes of pregnancy, including decreased ureteral peristalsis, mechanical compression of the ureters, decreased detrusor tone, and incomplete bladder emptying, may predispose pregnant woman to pyelonephritis. Anemia is a commonly described complication of pyelonephritis [1–6]. The physiology of this association is poorly understood. Confusing the picture is the fact that anemia itself is a common complication of pregnancy and is associated with preterm delivery and small for gestational age infants [7, 8]. Theories regarding the etiology of pyelonephritis-associated anemia include overhydration at diagnosis, endotoxin mediated hemolysis, renal erythropoietin suppression, and anemia of chronic disease [4, 9–11]. Despite the known association of pyelonephritis with anemia, there are minimal data describing the effects of anemia related to pyelonephritis on pregnancy outcomes. This study was initiated to evaluate pregnancies
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