Betamethasone is administered antenatally to a woman admitted with threatened preterm labour at 30 weeks gestation. The therapeutic basis for this intervention is:

• A Tocolysis through relaxation of uterine smooth muscle
• B Acceleration of fetal renal maturation improving amniotic fluid volume
• C Suppression of maternal antibody mediated placental inflammation
• D Induction of fetal pulmonary surfactant synthesis, reducing respiratory distress syndrome ✓

Explanation

Antenatal corticosteroids cross the placenta and stimulate fetal type II pneumocyte maturation, increasing production of surfactant phospholipids and surfactant proteins. Given between 24 and 34 weeks of gestation, a course of betamethasone significantly reduces neonatal respiratory distress syndrome, intraventricular haemorrhage and neonatal mortality. Betamethasone is preferred over dexamethasone in Indian practice because of its longer half-life and less frequent dosing. It has no tocolytic action whatsoever.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.