A 32-year-old multigravida (G3P2) from Delhi presents at 28 weeks of gestation for a routine antenatal visit. Fundal height is 26 cm (2 cm less than expected). Ultrasound confirms IUGR with estimated fetal weight of 900 g (5th centile). Umbilical artery Doppler shows pulsatile flow with normal diastolic component (S/D ratio 3.2). Cerebroplacental ratio is 1.8 (normal > 1.08). Middle cerebral artery peak systolic velocity is normal. Amniotic fluid volume is normal. Maternal blood pressure is 140/90 mmHg, and urine dipstick shows 1+ proteinuria. What is the most appropriate next step in management?