title: Risk factors associated with true knots of the umbilical cord.
abstract: OBJECTIVE
  To determine obstetrical risk factors and pregnancy outcome of fetuses with true knot of the umbilical cord.
  
  
  METHODS
  Study population included 69,139 singleton deliveries occurring between the years 1990-1997. Data were retrieved from the database of the Soroka University Medical Center. Fetuses with malformations were excluded.
  
  
  RESULTS
  The incidence of true knots was 1.2% (841/69,139). In a multivariate analysis the following factors were found to be significantly associated with true knot of cord: grandmultiparity, chronic hypertension, hydramnios, patients who undergone genetic amniocentesis, male gender and cord problems (prolapse of cord and cord around the neck). The incidence of fetal distress and meconium stained amniotic fluid was significantly higher among patients with true knots of cord (7% versus 3.6%, P<0.001 and 22% versus 16%, respectively, P<0.0001). Moreover, there was a four-fold higher rate of antepartum fetal death among those fetuses (1.9% versus 0.5%, P<0.0001). In addition, fetuses with true knots of the umbilical cord were more often delivered by a cesarean section (130/841 versus 711/68,298, P<0.0001). The following obstetrical factors were found to be significantly correlated to true knots of the umbilical cord in a multiple logistic regression model: gestational diabetes, hydramnios, patients undergoing genetic amniocentesis, male fetuses.
  
  
  CONCLUSIONS
  Patients with hydramnios, who underwent genetic amniocentesis and those carrying male fetuses are at an increased risk for having true knots of the umbilical cord. Thus, careful sonographic and Doppler examinations should be seriously performed in these patients for detection of the complication of the umbilical cord.
authors.affiliation: Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Hershkovitz
authors.forename: T
authors.initials: T
authors.lastname: Silberstein
authors.forename: E
authors.initials: E
authors.lastname: Sheiner
authors.forename: I
authors.initials: I
authors.lastname: Shoham-Vardi
authors.forename: G
authors.initials: G
authors.lastname: Holcberg
authors.forename: M
authors.initials: M
authors.lastname: Katz
authors.forename: M
authors.initials: M
authors.lastname: Mazor
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid; D002585:Cesarean Section; D016640:Diabetes, Gestational / Q000150:complications; D005260:Female; D005313:Fetal Death / Q000209:etiology; D005315:Fetal Diseases / Q000473:pathology*; D005316:Fetal Distress / Q000209:etiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008470:Meconium; D006831:Polyhydramnios / Q000150:complications; D011247:Pregnancy; D012307:Risk Factors; D012727:Sex Characteristics; D014102:Torsion Abnormality; D014470:Umbilical Cord / Q000473:pathology*