Changes in Biophysical Parameters and Fetoplacental Circulation After Maternal Betamethasone Administration: A Prospective Observational Study

Abstract

Introduction-Antenatal corticosteroids are administered to all antenatal women with threatened preterm labor to avoid respiratory distress syndrome (RDS) because of insufficient surfactant production by immature alveolar pneumocytes. But corticosteroid have certain side effects like transient fetal hypoxemia which may be perceived as signs of fetal distress warranting a preterm birth.

Objective & method- We planned a prospective observational study to study these hypoxemic changes produce by antenatal corticosteroids in 156 patients of threatened preterm labor, by observing biophysical profile (BPP) and umbilical and middle cerebral artery pulsatility index (PI), before corticosteroid administration and 4, 8 and 24 hours, and 3 days after it, till the changes revert back to normal.

Results- It was observed that there was a significant decrease in biophysical profile 4 to 8 hours after receiving betamethasone. However, all these changes reversed to normal values within 3 days. The pulsatility index of umbilical and middle cerebral artery after betamethasone administration significantly reduced after 4 hours whereas the changes seen after that were not significant and came to normal after 24 hours. Out of total 156 patients who had transient signs of hypoxemia, 132 (84.61%) could reach term gestational, because of close monitoring & awareness of transient nature of hypoxemic effects

Conclusion-Study emphasizes the need of understanding the pattern of changes in BPP and doppler studies after corticosteroid administration to prevent unnecessary iatrogenic delivery of preterm fetus