title: Low amniotic fluid volume is poorly identified in singleton and twin pregnancies using the 2 x 2 cm pocket technique of the biophysical profile.
abstract: BACKGROUND
  This study was done to determine the accuracy of the 2 x 2 cm pocket identifying low amniotic fluid (AF) volume in singleton and twin pregnancies.
  
  
  METHODS
  The AF volume was evaluated by ultrasonography for the presence of a 2 x 2 cm pocket before amniocentesis. The actual AF volume was then determined by a diazo-dye reaction with subsequent spectrophotometric analysis using paraminohippurate.
  
  
  RESULTS
  The AF volume was low in 21 of the 79 singleton pregnancies and normal in 47; hydramnios was present in 11. Among amniotic sacs of the 60 twin pairs, oligohydramnios was found in 33 amniotic sacs. normal AF volume in 80 sacs, and high volume in 7. An AF pocket smaller than 2 x 2 cm was identified in only 3 of the 79 singleton pregnancies and in only 2 of the 120 twin amniotic sacs.
  
  
  CONCLUSIONS
  Judging AF volume on the basis of a 2 x 2 cm pocket misses more than 90% of cases of oligohydramnios in singletons and twins.
authors.affiliation: Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
authors.forename: E F
authors.initials: EF
authors.lastname: Magann
authors.forename: B G
authors.initials: BG
authors.lastname: Nevils
authors.forename: S P
authors.initials: SP
authors.lastname: Chauhan
authors.forename: N S
authors.initials: NS
authors.lastname: Whitworth
authors.forename: J H
authors.initials: JH
authors.lastname: Klausen
authors.forename: J C
authors.initials: JC
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000000981:diagnostic imaging*; D055592:Biophysical Phenomena; D001703:Biophysics; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005865:Gestational Age; D006801:Humans; D016104:Oligohydramnios / Q000175:diagnosis*; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple; D015203:Reproducibility of Results; D013053:Spectrophotometry; D014427:Twins; D014463:Ultrasonography; D010130:p-Aminohippuric Acid
chemical_list: D010130:p-Aminohippuric Acid