ABSTRACT
A recent, prospective randomized trial has suggested that long-term use of prophylactic
beta-adrenergic blocking agents may slow the rate of aortic dilation in those patients
with Marfan's syndrome exhibiting evidence of existing dilation. Accordingly, administration
of such medication from the midtrimester onward has been advocated in these patients.
Acute oral administration of propranolol (80 mg) has been shown to depress fetal heart
rate response to vibroacoustic stimulation. We present a case in which chronic administration
of propranolol 150 mg/day to a patient with Marfan's syndrome with existing aortic
root dilation was associated with repeated abnormal intrapartum fetal heart rate responses
to vibroacoustic stimulation. Subsequent delivery of a nonhypoxic, nonacidotic infant
suggests that maternal administration of β-blockers should be considered in the interpretation
of results of fetal vibroacoustic stimulation. This case also supports that in similar
clinical presentations, ultrasonographic confirmation of the fetal startle response,
or alternatively observation of the resulting fetal recoil may be utilized rather
than the fetal heart rate, which may be modulated by maternal medications.
Keywords
Marfan's syndrome - propranolol - electronic fetal monitoring - vibroacoustic stimulation
- fetal response - biophysical profile
