The predictors of successful methotrexate treatment of tubal ectopic pregnancy

J Obstet Gynaecol. 2024 Dec;44(1):2361456. doi: 10.1080/01443615.2024.2361456. Epub 2024 Jun 12.

Abstract

Background: The pre-treatment characteristics of the patient and ectopic pregnancy to determine the patients who are likely to successfully respond to methotrexate (MTX) therapy remain controversial. This study investigated the outcomes of ectopic pregnancy after one and two MTX doses and their independent predictors.

Methods: Retrospective cross-sectional study of women who consented to MTX treatment in 2017-2018 at our institution (N = 317). Of these, patients with Caesarean scar pregnancies were excluded because they require different treatment protocols (n = 25). All patients were treated according to our institution's protocol based on international guidelines and standardised across the three hospitals included in the current study. We retrieved patients' demographics, laboratory, ultrasonography, and clinical characteristics from our hospital database. Serum β-human chorionic gonadotropin (β-hCG) was measured using electrochemiluminescence immunoassay; ectopic pregnancy was diagnosed using ultrasonography (transvaginal probe).

Results: Two ninety-two patients were included in the current analysis. Age, pre-treatment β-hCG levels, sonographic presence of yolk sac, presence of foetal cardiac activity, and pelvic pain were significantly different between patients with successful and unsuccessful outcomes. Younger age (adjusted odds ratio [aOR] 2.33, 95% confidence interval (CI) 1.16-4.66, p = .017), no pelvic pain (aOR 2.65, 95%CI 1.03-6.83, p = .043), lower initial β-hCG level (aOR 1.32, 95%CI 1.08-1.59, p = .005), and absence of foetal cardiac activity (aOR 12.63; 95% CI 1.04-153.6; p = .047) were independently associated with success. Treatment failure odds were >2 folds higher for each 10-year age increase (p = .017), 32% higher for each 1000 IU/L increase in initial β-hCG level (p = .005), and >2 folds higher in presence of pelvic pain (p = .043).

Conclusions: MTX is effective in most patients, averting invasive surgery, which might affect fertility. Pre-treatment β-hCG levels, age, pelvic pain, and foetal cardiac activity was independently associated with outcomes. Research should assess the relationship between the ectopic pregnancy size and treatment outcomes and refine β-hCG titres where treatment would be ineffective.

Keywords: Ectopic pregnancy; medical management; methotrexate; pregnancy of unknown location.

Plain language summary

Ectopic pregnancy is a pregnancy that occurs outside the uterus. It needs to be identified and treated quickly to prevent serious health complications. Ectopic pregnancies can be treated surgically or medically using a drug called methotrexate. Medical treatment of ectopic pregnancy is not always successful. Identifying the factors that predict the failure of medical treatment helps patients and doctors to choose more accurately between surgical and medical treatment options.A total of 292 women who received methotrexate for ectopic pregnancy and the factors that influence the outcomes of treatment were examined, 39 patients had treatment failure and required surgery. Older age, higher initial levels of β-human chorionic gonadotropin (β-hCG) hormone, the presence of pelvic pain, and foetal cardiac activity had increased risk of treatment failure. In the future, research could consider the relationship between the size of the ectopic pregnancy and the treatment outcomes and refine the β-hCG level cut-off for better treatment effects.

MeSH terms

  • Abortifacient Agents, Nonsteroidal* / therapeutic use
  • Adult
  • Chorionic Gonadotropin, beta Subunit, Human* / blood
  • Cross-Sectional Studies
  • Female
  • Humans
  • Methotrexate* / therapeutic use
  • Pregnancy
  • Pregnancy, Tubal* / blood
  • Pregnancy, Tubal* / drug therapy
  • Retrospective Studies
  • Treatment Outcome

Substances

  • Methotrexate
  • Abortifacient Agents, Nonsteroidal
  • Chorionic Gonadotropin, beta Subunit, Human