In the methotrexate single-dose protocol for ectopic pregnancy, which β-hCG trend on day 4 vs day 7 indicates treatment success?

• A Any decrease in β-hCG from day 1 to day 7
• B β-hCG plateau (change <15%) between day 4 and day 7
• C β-hCG level below 1000 mIU/mL by day 7
• D A decrease of >15% between day 4 and day 7 β-hCG ✓

Explanation

After single-dose methotrexate (50 mg/m² IM), β-hCG characteristically rises between day 1 and day 4 (due to initial cellular lysis releasing hCG) — this early rise is expected and should not trigger retreatment. Between day 4 and day 7, a fall of ≥15% in β-hCG indicates successful treatment. If the fall is <15%, a second dose is given. If β-hCG does not fall appropriately after two doses, surgical intervention is indicated. Weekly monitoring continues until β-hCG is undetectable.

Reference: Williams Obstetrics, 26th ed.

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Written and medically reviewed by the StethoPrep medical team.