title: Effect of halogen light stimulation on nonstress testing.
abstract: OBJECTIVE
  This study was undertaken to determine whether external stimulation using a halogen light source influences fetal heart rate (FHR) responsiveness and nonstress test results.
  
  
  METHODS
  A total of 107 patients at 32 to 42 weeks' gestation undergoing a nonstress test were randomly assigned to have either transabdominal light stimulation or no light stimulation. The light (Vector Compact Sport Spot, Ft Lauderdale, Fla) was turned on for 10 seconds. If no qualifying FHR acceleration was observed, then the stimulus was repeated at 10-minute intervals for a maximum of 3 times. The investigators were blinded as to light stimulation for FHR interpretation.
  
  
  RESULTS
  Reactive results were present in 52 cases in each group. Light stimulation led to a significantly shorter time (P <.02) until the first FHR acceleration (difference: 2.1 minutes; 95% CI 0.4-3.8 minutes). The height and width of the first acceleration were indistinguishable between groups. The time until a reactive result was significantly shorter after light stimulation (difference: 4.2 minutes; 95% CI 2.0-6.4 minutes).
  
  
  CONCLUSIONS
  The earlier onset of FHR accelerations after halogen light stimulation prompted a more rapid reactive nonstress test result.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University of New Mexico, Albuquerque, NM 87131-0001, USA. bcaridi@salud.unm.edu
authors.forename: Bruno J
authors.initials: BJ
authors.lastname: Caridi
authors.forename: Jay M
authors.initials: JM
authors.lastname: Bolnick
authors.forename: Beverly G
authors.initials: BG
authors.lastname: Fletcher
authors.forename: William F
authors.initials: WF
authors.lastname: Rayburn
mesh_terms: D016001:Confidence Intervals; D005260:Female; D005316:Fetal Distress / Q000175:diagnosis*; D005323:Fetal Monitoring / Q000379:methods*; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D008027:Light; D010775:Photic Stimulation; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011336:Probability; D012016:Reference Values; D012680:Sensitivity and Specificity