A 32-year-old woman comes to the emergency department due to a | Obstetrics & Gynecology

A 32-year-old woman comes to the emergency department due to abdominal pain and nausea that began 2 days earlier but has become increasingly severe over the last 3 hours. The patient has passed several vaginal blood clots in the last hour. She has a history of irregular menstrual cycles and is not sure of the date of her last period. She was diagnosed with a bicornuate uterus 2 years ago during an infertility evaluation. The patient has no other medical conditions and has had no surgeries. BMI is 28 kg/m2. Blood pressure is 90/56 mm Hg and pulse is 120/min. Abdominal examination shows guarding with decreased bowel sounds. Speculum examination shows moderate bleeding with clots from the cervix. A urine pregnancy test is positive. Transvaginal ultrasound reveals a gestational sac at the upper left uterine cornu and free fluid in the posterior cul-de-sac of the pelvis. Which of the following is the best next step in management of this patient?