A 32-year-old multiparous woman at 29 weeks gestation with gestational hypertension is referred for ultrasound. Fetal weight is estimated at 3rd percentile, amniotic fluid volume is reduced (AFI 6 cm), and umbilical artery Doppler shows elevated pulsatility index with preserved end-diastolic flow. Fetal heart rate is 145 bpm with normal variability on cardiotocography. What is the most appropriate next step in management?