A 28-year-old multiparous woman at 28 weeks gestation presents with vaginal bleeding and mild abdominal discomfort for 6 hours. Vital signs: BP 118/74 mmHg, HR 88/min, RR 16/min. Uterus is mildly tender but soft. Speculum shows minimal vaginal bleeding. Ultrasound reveals a small retroplacental clot (1.5 cm) with normal fetal heart rate (155/min) and normal amniotic fluid volume. Hemoglobin is 10.8 g/dL (baseline 11.5 g/dL). What is the most appropriate management?