title: The effect of uterine contractions on fetal oxygen saturation.
abstract: OBJECTIVE
  To find out what happens to fetal arteriolar oxygen saturation during a uterine contraction.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Labour ward, St James's University Hospital, Leeds.
  
  
  METHODS
  Eighteen women in normal labour monitored with a fetal scalp surface pulse oximetry sensor, an intrauterine pressure catheter, and a head to cervix force transducer.
  
  
  METHODS
  The effect of intrauterine pressure and head to cervix force on fetal arteriolar oxygen saturation was examined using time series analysis and a regression model of 159 contractions.
  
  
  METHODS
  Fetal oxygen saturation during a contraction.
  
  
  RESULTS
  The average oxygen saturation drops after a contraction. The greatest drop in oxygen saturation is reached 92 s after the peak of a contraction and takes approximately 1 min 30 s to recover (P = 0.036).
  
  
  CONCLUSIONS
  Uterine contractions during normal labour affect fetal oxygen saturation.
authors.affiliation: Leeds General Infirmary, Academic Unit of Obstetrics and Gynaecology, UK.
authors.forename: H
authors.initials: H
authors.lastname: McNamara
authors.forename: N
authors.initials: N
authors.lastname: Johnson
mesh_terms: D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D011247:Pregnancy; D011312:Pressure; D011446:Prospective Studies; D014590:Uterine Contraction / Q000502:physiology*
chemical_list: D010100:Oxygen