Chronic Hypertension in Pregnancy

A 35-year-old woman who has never been pregnant and who has a 5-year history of hypertension wants to become pregnant. She has stopped using contraception. Her only medication is lisinopril at a dose of 10 mg per day. Her blood pressure is 124/68 mm Hg, and her body-mass index (the weight in kilograms divided by the square of the height in meters) is 27. What would you advise?