title: Is oligohydramnios in postterm pregnancy associated with redistribution of fetal blood flow?
abstract: OBJECTIVE
  Our purpose was to determine whether postterm patients with oligohydramnios differ in their fetal and umbilical blood flow distribution from those with a normal volume of amniotic fluid.
  
  
  METHODS
  Pulsed-wave Doppler imaging was used prospectively to determine the resistance index in the fetal middle cerebral, renal, and umbilical arteries in 57 postterm (i.e., > 41 weeks' gestation) pregnancies. Semiquantitative assessment of amniotic fluid volume was obtained by use of the ultrasonographically determined amniotic fluid index.
  
  
  RESULTS
  Oligohydramnios (amniotic fluid index < 5 cm) was detected in 15 patients; 42 patients with a normal amniotic fluid index served as a control group. The various resistance index values and the ratio s among them were not significantly different when patients with oligohydramnios were compared with controls (0.51 +/- 0.1 vs 0.52 +/- 0.06, 0.63 +/- 0.1 vs 0.64 +/- 0.08, and 0.71 +/- 0.08 vs 0.73 +/- 0.05 for the umbilical, middle cerebral, and renal arteries, respectively). However, the mean birth weight (in grams) was significantly lower (3297 +/- 438 vs 3742 +/- 448, p < 0.003), in the oligohydramnios group.
  
  
  CONCLUSIONS
  Oligohydramnios was not associated with a major redistribution of blood flow in postterm patients, suggesting that the cause of oligohydramnios in these patients is related to birth weight rather than to renal perfusion.
authors.affiliation: Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: I
authors.initials: I
authors.lastname: Bar-Hava
authors.forename: M Y
authors.initials: MY
authors.lastname: Divon
authors.forename: M
authors.initials: M
authors.lastname: Sardo
authors.forename: Y
authors.initials: Y
authors.lastname: Barnhard
mesh_terms: D000653:Amniotic Fluid / Q000502:physiology; D001724:Birth Weight; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D005260:Female; D005333:Fetus / Q000098:blood supply*; D006801:Humans; D007231:Infant, Newborn; D016104:Oligohydramnios / Q000503:physiopathology*; D011247:Pregnancy; D011273:Pregnancy, Prolonged / Q000502:physiology*; D011446:Prospective Studies; D012077:Renal Artery / Q000503:physiopathology; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000503:physiopathology; D014655:Vascular Resistance