Blink-startle reflex habituation in 30-34-week low-risk fetuses.
OBJECTIVE
To investigate whether the blink-startle reflex (BSR) is a good marker of habituation to vibroacoustic stimulation in healthy preterm fetuses.


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).


CONCLUSIONS
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.
Bellieni
Carlo V
CV
Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy. bellieni@iol.it
Severi
Filiberto
F
Bocchi
Catarina
C
Caparelli
Ninetta
N
Bagnoli
Franco
F
Buonocore
Giuseppe
G
Petraglia
Felice
F
D000161:Acoustic Stimulation; D000328:Adult; D001767:Blinking / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000502:physiology*; D005865:Gestational Age; D006185:Habituation, Psychophysiologic; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012016:Reference Values; D013216:Reflex, Startle / Q000502:physiology*; D016216:Ultrasonography, Prenatal