A 30-year-old woman with a previous salpingectomy for left ectopic pregnancy presents with 6 weeks amenorrhea and beta-hCG of 2400 IU/L. Transvaginal ultrasound shows an empty uterus and no adnexal mass. What is the MOST appropriate next step?

• A Administer methotrexate 50 mg/m² IM immediately
• B Repeat beta-hCG in 48 hours to assess discriminatory zone interpretation ✓
• C Diagnostic laparoscopy to exclude remaining ectopic risk
• D Administer mifepristone and misoprostol to rule out intrauterine pregnancy

Explanation

When beta-hCG is 2400 IU/L (below the discriminatory zone of 3500 IU/L for transvaginal ultrasound or 1500–2000 IU/L at some centers), an empty uterus may represent a very early intrauterine pregnancy, a failing IUP, or an ectopic. The appropriate step is serial beta-hCG measurement every 48 hours. A rise of <53% in 48 hours is abnormal and suggests ectopic or failing IUP; a rise >53% suggests viable IUP. Methotrexate must not be given without confirmed ectopic; it would terminate a possible viable IUP.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.