Gestational hypertension

A 25-year-old woman, gravida 2, para 1, at 22-weeks gestation comes to the clinic for a routine obstetrics evaluation. She has no complaints today as her morning nausea and vomiting have resolved. She denies headaches, blurry vision, and dizziness. Medical history is noncontributory and the only medication she takes is a prenatal vitamin. Her temperature is 37.0°C (98.6°F), pulse is 76/min, respirations are 12/min, and blood pressure is 150/90 mm Hg. Physical examination shows only mild pitting edema in her lower extremities and an unremarkable neurological examination. The patient is allowed to sit quietly for twenty minutes, and repeat blood measurement is 145/85 mmHg. Urinalysis is negative for the presence of protein, casts, or blood. Which of the following is the most likely diagnosis?