Fetal Bradyarrhythmia and Abnormal Doppler Velocimetry in A Preterm Fetus: Management in A Resource-Constrained Setting: Case Report

Abstract

Background: Benign cardiac rhythm abnormalities of short duration have been noted in 2 % of second to third-trimester fetuses.  However, their association with abnormal doppler velocimetry is rare. Fetal bradycardia is an ominous sign whose occurrence at preterm gestation adds dilemma to the management of such cases due to additional risks associated with prematurity if the fetus is delivered prematurely, especially in a resource-constrained setting. Case presentation: The fetus of a 29-year-old primipara was found to have an irregular fetal heart rate of 90 beats per minute at 29 weeks of gestation on routine antenatal evaluation. An ultrasound scan confirmed the bradycardia with ectopic beats and an appropriate for gestational age fetus with no cardiac/other structural abnormality or features of hydrops.  Doppler velocimetry revealed intermittent absent flow in the umbilical artery and ductus venosus with a reversal of flow in the middle cerebral artery. Following maternal evaluation, she was diagnosed to have gestational diabetes mellitus and had a negative antinuclear antibody test. She had a course of dexamethasone for fetal lung maturation and was commenced on insulin and dietary modification. The fetal heart rate normalised 48 hours after the administration of dexamethasone. A multidisciplinary care approach was instituted with a weekly biophysical profile and fetal doppler studies. The fetal heart irregularity persisted till 36 weeks’ gestation and the abnormal doppler parameters completely normalised by 35 weeks gestation. She was delivered at term of a normal infant with a good APGAR score that weighed 3.2kg. The umbilical cord was noted to be marginally inserted into the placenta but with a normal number of vessels. The neonate had normal electrocardiographic and echocardiographic findings and an uneventful neonatal period. Conclusion: Bradyarrhythmia in the preterm fetus even when associated with abnormal doppler velocimetry may resolve spontaneously and not indicate an urgent need for delivery. However, intensive fetal surveillance is warranted to balance the risk of prematurity against perinatal loss.