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.

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.

Long-term effects of antepartum bed rest on offspring

We studied the children of mothers who were confined to bed during pregnancy for more than 15 consecutive days (mean 3.69 months) in the years 1986-1990 (bed rest offspring; BRO). We studied 86 children: 43 BRO and 43 control children. Data were obtained by means of a 20-item questionnaire filled in by the mothers. The BRO group differed from the control group in incidence of allergies (p = 0.005), motion sickness (p = 0.03), and need to be rocked to fall asleep (p = 0.01). More BRO born at term than controls played musical instruments later in life. Two possible explanations for more allergies among the BRO group are the use of beta-stimulating drugs against premature delivery and the effects of prolonged stress on the developing immune system. Understimulation of the developing vestibular system during gestation may affect some aspects of its development and may explain the higher incidence of motion sickness and need for vigorous rocking in BRO.