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