Mx. Ransom et al., SERUM PROGESTERONE AS A PREDICTOR OF METHOTREXATE SUCCESS IN THE TREATMENT OF ECTOPIC PREGNANCY, Obstetrics and gynecology, 83(6), 1994, pp. 1033-1037
Objective: To determine the prognostic value of a single serum progest
erone measurement for resolution of ectopic pregnancy following methot
rexate therapy. Methods: All patients attending our infertility clinic
had quantitative beta-hCG and serum progesterone measured prospective
ly within the first week of missed menses. Ectopic pregnancy was diagn
osed nonsurgically by poorly rising beta-hCG levels and lack of eviden
ce of intrauterine gestation by transvaginal sonography. Once diagnose
d, candidates received a single intramuscular injection of methotrexat
e, 50 mg/m(2). Treatment outcome was categorized as either resolved or
requiring surgery, and interpreted with respect to serum progesterone
measured within 24 hours of methotrexate administration. Results: Twe
nty-one patients were treated for ectopic pregnancy. Eleven had serum
progesterone levels greater than 10 ng/mL and ten patients had levels
of 10 ng/mL or less. The two groups did not differ significantly with
respect to age, weight, hCG at the time of methotrexate administration
, or amount of methotrexate administered. Of the 11 patients with seru
m progesterone levels above 10 ng/mL, only five had pregnancies that r
esolved following methotrexate. All ten patients with levels less than
10 ng/mL had resolution. This difference is significant (P = .009, 95
% confidence interval 0.26-0.84). There was no improvement in the pred
iction of outcome when either the absolute or daily percentage increas
e of hCG was determined before methotrexate administration. Conclusion
: A single serum progesterone measurement above or below 10 ng/mL is u
seful for predicting resolution of tubal pregnancy with methotrexate t
reatment.