Blink-startle reflex habituation in 30-34-week low-risk fetuses

J Perinat Med. 2005;33(1):33-7. doi: 10.1515/JPM.2005.005.


Objective: To investigate whether the blink-startle reflex (BSR) is a good marker of habituation to vibroacoustic stimulation in healthy preterm fetuses.

Materials and methods: A total of 22 women with uncomplicated pregnancies at 30-34 weeks participated in the study. Vibroacoustic stimulus was repeatedly applied to the maternal abdomen above the fetal head for a period of 2 s every 10 s. Fetal eye tightening monitored by ultrasound within 2 s of the stimulus was considered a positive response. The habituation rate was defined as the number of stimuli applied before the fetus stopped responding to two consecutive stimuli. Results were compared using the Mann-Whitney U-test.

Results: All 22 fetuses showed habituation at a rate that varied from 1 to 9 (mean 4.2+/-1.8).

Conclusion: BSR is a good marker of habituation in preterm fetuses. Further study is needed to ascertain whether abnormal BSR habituation could be a sign of fetal distress.

Publication types

  • Evaluation Study

MeSH terms

  • Acoustic Stimulation
  • Adult
  • Blinking / physiology*
  • Female
  • Fetus / physiology*
  • Gestational Age
  • Habituation, Psychophysiologic
  • Humans
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Trimester, Third
  • Reference Values
  • Reflex, Startle / physiology*
  • Ultrasonography, Prenatal