Objective: To analyze the therapeutic effect and influencing factors of single dose methorexate (MTX) on tubal pregnancy patients with low and medium level β-hCG

and to provide some basis for clinical selection of reasonable treatment plans. Methods: A retrospective study was carried out in 214 cases of tubal pregnancy with serum β-hCG lower than 1 500 IU/L using single dose MTX treatment and 80 cases of serum β-hCG 1 000-1 500 IU/L undergoing operation during the same period in our department from January to December 2020. According to the level of serum β-hCG before single dose MTX initial treatment

they were divided into three subgroups: group A (β -hCG<500 IU/L) ; group B (500 IU/L≤β-hCG<1 000 IU/L) ; group C (1 000 IU/L≤β-hCG<1 500 IU/L)

comparing the clinical efficacy and analyzing the factors of influencing the therapeutic effect. Results: ①There were no significant differences in mass size

pelvic effusion depth and hospital day among the three groups (P >0.05). Patients in group C had the highest hospitalization cost and transfer rate of surgery

and the lowest success rate of initial treatment (P<0.05)

but no statistically significant differences in hospitalization cost

transfer rate of surgery and success rate between group A and group B (P >0.05). There were no significant differences in the incidence of adverse reactions and persistent ectopic pregnancy among the three groups after single dose MTX treatment (P >0.05). The time from the first time to normal blood β-hCG in the three groups was statistically significant different (P<0.05)

with the shortest in group A and the longest in group C. ②In patients with serum β-hCG in the range of 1 000-1 500 IU/L

the mass size and pelvic ef-fusion depth were significant different between surgical treatment group and single dose MTX treatment group (P<0.05)

the length of hospital stay and the time for serum β-hCG to return to normal were shorter in the surgical treatment group than in the single dose MTX treatment group (P<0.05). ③For single dose MTX treatment patients

there were no significant differences in age and depth of pelvic effusion between successful group and failed group (P >0.05)

but there were significant differences in β-hCG level and mass size between two groups (P<0.05). ④In multivariate logistic regression analysis

1 000 IU/L≤serum β-hCG<1 500 IU/L (OR=3.714

95%CI=1.439-9.583)

and mass>3.5 cm (OR=3.022

95%CI=1.298-7.037) was a risk factor for failure of single dose MTX therapy. Conclusion: Patients with β-hCG≥1 000 IU/L have a higher failure rate of single-dose MTX treatment

and serum β-hCG≥1 000 IU/L and mass>3.5 cm are independent risk factors for the success rate of single dose MTX treatment. Surgical treatment seems to be more cost-effective for patients with β-hCG≥1 000 IU/L.