title: Eyelid movements in normal human fetuses.
abstract: OBJECTIVE
  We undertook this study to investigate the characteristics of blinking activity in healthy human fetuses.
  
  
  METHODS
  Blinking activity was studied sonographically in healthy fetuses between 33 and 42 weeks' menstrual age. Horizontal and coronal sonographic views of the eye were obtained and videotaped. Fetal blinking movements were analyzed by reviewing the videotape in slow motion. Fetal vibroacoustic stimulation was also used when clinically indicated.
  
  
  RESULTS
  We examined a total of 18 healthy fetuses. Fetal blinking was detected in 89% of cases, with a mean frequency of 6.2 movements per 60-minute observation period. Vibroacoustic stimulation was associated with increased fetal blinking in the 6 fetuses in which it was applied (mean, 15.3 movements per 60-minute observation period).
  
  
  CONCLUSIONS
  Blinking is a normal fetal activity. The increased frequency of blinking activity associated with vibroacoustic stimulation may be considered a part of the normal startle reflex.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Nassau University Medical Center, Third Floor, Women's Pavilion, 2201 Hempstead Turnpike, East Meadow, New York 11554, USA.
authors.forename: Boris M
authors.initials: BM
authors.lastname: Petrikovsky
authors.forename: Gary
authors.initials: G
authors.lastname: Kaplan
authors.forename: Nancy
authors.initials: N
authors.lastname: Holsten
mesh_terms: D000161:Acoustic Stimulation; D001767:Blinking / Q000502:physiology*; D005143:Eyelids / Q000502:physiology; D005260:Female; D005333:Fetus / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D014743:Videotape Recording