Ectopic pregnancy medical therapy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview[edit | edit source]

There has only been one randomized controlled trail comparing medical to surgical therapy, and there was no difference as far as elimination of the EP or tubal preservation, however the methotrexate (MTX) group had a higher incidence of side effects.

Medical Therapy[edit | edit source]

Early treatment of an ectopic pregnancy with the antimetabolite methotrexate has proven to be a viable alternative to surgical treatment^[1] since 1933.^[2] If administered early in the pregnancy, methotrexate can disrupt the growth of the developing embryo causing the cessation of pregnancy. As actively proliferating trophoblasts have a high rate of de-novo purine and pyrimidine synthesis, they are especially vulnerable to MTX. MTX therapy is generally reserved for EPs < 4 cm on ultrasound in stable patients.

• Dosing regimens include:

  • Variable dose: MTX 1 mg/kg IM qod, alternating with leucovorin 0.1 mg/kg IM qod. This is continued until the beta-HCG falls ≥ 15% in 48 hours, or 4 doses of MTX have been given.
  • Single dose: MTX 50 mg/m² IM (can be repeated if beta-HCG on day 7 is ≥ level on day 4). Although more convenient, it has a slightly higher risk of persistent EP.
  • Direct injection at the site of implantation has a lower success rate, still requires laparoscopy or ultrasound guidance, and has no benefits consistent with systemic MTX.
  • Transient pelvic pain is relatively common with MTX therapy, and it is often difficult to distinguish therapeutic pain from that of a rupturing ectopic.
  • Expectant management with watchful waiting works in ~ 68% of patients.

References[edit | edit source]

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