title: Kleihauer-betke testing is important in all cases of maternal trauma.
abstract: BACKGROUND
  In maternal trauma, the Kleihauer-Betke (KB) test has traditionally been used to detect transplacental hemorrhage (TPH), so that Rh-negative women could receive appropriate Rh immune prophylaxis. Reasoning that the magnitude of TPH would reflect uterine injury, we evaluated Kleihauer-Betke testing as an independent predictor of preterm labor (PTL) after maternal trauma.
  
  
  METHODS
  Admissions to the Shock Trauma Center, University of Maryland, from January 1996 to January 2002, were reviewed. Of 30,362 trauma patients admitted, 166 were pregnant, and 93 of these underwent electronic fetal monitoring. Their records were abstracted for demographics, injury type, three separate trauma scores, documented uterine contractions, PTL (contractions with progressive cervical change), and serious perinatal complications. In 71 cases, transplacental hemorrhage was assessed by maternal KB test.
  
  
  RESULTS
  TPH, defined as KB-positive for greater than 0.01 mL of fetal blood in the maternal circulation, occurred in 46 women. Forty-four had documented contractions (25 had overt PTL) and 2 had no contractions. In 25 women with a negative KB test, none had uterine contractions. All patients with contractions or PTL had positive KB tests. By logistic regression, KB test result was the single risk factor associated with PTL (p < 0.001; likelihood ratio, 20.8 for positive KB test). Compared with other sites, abdominal trauma was associated more often with uterine contractions (p < 0.001), PTL (p = 0.001), and a positive KB test (p < 0.001, chi). None of the trauma scoring systems predicted PTL.
  
  
  CONCLUSIONS
  Kleihauer-Betke testing accurately predicts the risk of preterm labor after maternal trauma. Clinical assessment does not. With a negative KB test, posttrauma electronic fetal monitoring duration may be limited safely. With a positive KB test, the significant risk of PTL mandates detailed monitoring. KB testing has important advantages to all maternal trauma victims, regardless of Rh status.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Muench
authors.forename: Ahmet A
authors.initials: AA
authors.lastname: Baschat
authors.forename: Uma M
authors.initials: UM
authors.lastname: Reddy
authors.forename: Hugh E
authors.initials: HE
authors.lastname: Mighty
authors.forename: Carl P
authors.initials: CP
authors.lastname: Weiner
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Scalea
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Harman
mesh_terms: D000007:Abdominal Injuries / Q000150:complications*; D000293:Adolescent; D000328:Adult; D018890:Chemoprevention; D003955:Diagnostic Tests, Routine; D005260:Female; D005331:Fetomaternal Transfusion / Q000097:blood* / Q000209:etiology; D006801:Humans; D015601:Injury Severity Score; D016015:Logistic Models; D007752:Obstetric Labor, Premature / Q000097:blood* / Q000175:diagnosis; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood* / Q000175:diagnosis / Q000276:immunology; D011256:Pregnancy Outcome; D012204:Rh-Hr Blood-Group System / Q000097:blood; D018029:Rho(D) Immune Globulin / Q000008:administration & dosage
chemical_list: D012204:Rh-Hr Blood-Group System; D018029:Rho(D) Immune Globulin