Design: Retrospective cohort between December 2009 and June 2021.

Setting: Two tertiary hospitals

Patients or Participants: Women with confirmed tubal pregnancies and pretreatment hCG <2000 mIU/mL. Exclusion criteria were unrecorded pregnancy site, unconfirmed diagnosis, and surgical treatment upon diagnosis. 545 of 2114 (25.8%) women diagnosed with an ectopic pregnancy met our inclusion criteria. We compared women who underwent EM (N=201) with women who received MTX (N=344).

Interventions: Medical treatment consisted of a single-dose intra-muscular administration of MTX. Another MTX dose was given if Serum hCG levels decreased by less than 15% between days 4 to 7 post-treatment. EM was chosen only if a decrease in hCG levels was demonstrated.

Measurements and Main Results: The MTX group had higher pretreatment hCG and higher rates of yolk sac or embryo presence on ultrasound. Eventual surgical treatment rate was higher in the MTX group compared to the EM group [39 (11.3%) vs. 9 (4.5%), P=0.006], with no difference in the treatment failure rate or tubal rupture rate. In a subgroup analysis of women with pretreatment hCG between 1000-2000 mIU/ml, eventual surgical treatment, treatment failure, and tubal rupture rates did not differ between groups. Logistic regression analysis revealed that EM was independently associated with eventual surgical treatment (aOR 0.42, 95% CI 0.19-0.91), hCG levels <1000 mIU/ml (aOR 0.28, 95% CI 0.14-0.56), and endometriosis (aOR 9.20, 95% CI 3.55-23.81).

Conclusion: Expectant management of tubal pregnancies with pretreatment hCG levels <2000 mIU/ml and even between 1000-2000 mIU/ml and with a declining trend of hCG resulted in lower or comparable rates of eventual surgical treatment, when compared to MTX treatment. Treatment failure rates were also comparable between groups. These findings suggest that EM might serve as an alternative to medical treatment for a larger subset of patients than traditionally accepted.