Tawfiq et al identified risk factors associated with failure of a single dose of methotrexate to control an ectopic pregnancy. These can help identify who should receive an alternative therapy. The authors are from the University of Ottawa in Canada.


Inclusion criteria:

(1) ectopic pregnancy < 4 cm

(2) unruptured

(3) hemodynamically stable

(4) absence of fetal heart activity on ultrasonography


Single methotrexate dose = 50 mg per square meter BSA by injection


Criteria for failure of therapy:

(1) need for surgical treatment (usually due to tubal rupture with hemorrhage)

(2) failure of serum beta-hCG decline by 1 week after the dose


Risk factors for failure:

(1) serum beta-hCG > 4,000 IU/L (odds ratio 52)

(2) pelvic pain (without tenderness) (odds ratio 9)

(3) vaginal bleeding (odds ratio 6)



• Methotrexate should not be used with the serum beta-hCG > 4,000 IU/L.

• An equivalent cumulative odds ratio is seen when BOTH pelvic pain and vaginal bleeding are present.

• The use of methotrexate should be used with caution if EITHER pelvic pain or vaginal bleeding is present.



• The reference range for the methotrexate assay was not given but presumably is < 5 IU/L. The method was EIA on the Abbot Axsym.


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