Review Question - QID 213859

A 29-year-old woman presents to her gynecologist complaining of heavy menstrual bleeding for the past 2 years. In the past, her periods lasted for 4 days, and she soaked 3 pads per day. Now, they last for 6 days, and she soaks through 7-8 pads per day. Her last period was 3 weeks ago, and she noticed large clots. She reports increased fatigue starting 6 months ago and a 5 lb. weight gain in the last month. Her last pap smear was performed 1 year ago and was normal. She denies dysmenorrhea. She has a history of hypothyroidism and is currently taking levothyroxine. She is currently sexually active with her husband and is not using contraception. Her temperature is 98.6°F (37.0°C), blood pressure is 105/73 mmHg, pulse is 60/min, respirations are 17/min, and BMI is 39.4 kg/m2. Pelvic exam reveals a closed cervical os with an irregularly shaped abdominal mass with no adnexal tenderness. Laboratory studies are ordered as seen below.

TSH: 1.8 mIU/L
T4: 7.2 mcg/dL

Hemoglobin: 9.2 g/dL
Hematocrit: 31%
MCV: 76 fL

Urine:
hCG: Negative
Blood: Negative
Leukocytes: Negative
Bacteria: Negative

Which of the following is the most appropriate next step in management?