A 50-year-old G3P3 woman comes to the office reporting heavy periods, spotting between menses, fatigue and weakness. Over the past six months, she has noticed a significant increase in the amount of her menstrual bleeding, currently requiring a box of 30 pads for each month. She has noticed an increase in the amount of blood clots and cramping pain during menses. Her previous history is significant for hypertension for 10 years, controlled with hydrochlorothiazide and a postpartum bilateral tubal ligation 20 years ago. She has no history of abnormal Pap tests and no sexually transmitted infections. Blood pressure is 138/84; pulse, 82; respirations, 20; weight, 220 pounds; height, 5 feet, 8 inches. On pelvic exam, uterus is approximately 10-week size. She is non- tender on bimanual exam and no adnexal masses are appreciated. A Pap test one month ago was normal, hematocrit is 29 and she is asymptomatic. What is the next best step in the management of this patient?