Serum biochemistry correlates with the size of tubal ectopic pregnancy on sonography

Ultrasound Obstet Gynecol. 2006 Nov;28(6):826-30. doi: 10.1002/uog.3822.


Objective: To investigate whether there is a correlation between serum biochemistry (human chorionic gonadotropin (hCG), CA 125, progesterone and estradiol) and the common sonographic findings (blob sign, bagel sign or extrauterine gestational sac with cardiac activity) or size of a tubal ectopic pregnancy, and whether there is a difference in serum biochemistry between women with a tubal ectopic pregnancy who are hemodynamically unstable (tachycardia, hypotension, falling hemoglobin levels and/or acute severe abdominal pain) and those who are hemodynamically stable.

Methods: This was a prospective cohort study of 106 women with a tubal ectopic pregnancy. We noted transvaginal ultrasound examination findings including adnexal mass size, and the serum levels of hCG, CA 125, progesterone and estradiol. The data were analyzed retrospectively.

Results: The mean maternal and gestational ages were 30.7+/-5.7 years and 44+/-4.2 days, respectively. There was no correlation between serum markers and common sonographic findings. However, in the presence of the bagel sign on ultrasound, hemodynamic stability was more common (P=0.03). The mean serum hCG concentrations in tubal ectopic pregnancies<20 mm, 20-40 mm and >40 mm in size were 2225.3+/-3166.9, 4124.8+/-6121.4, and 11 011.8+/-12 670.1 IU/mL, respectively (P<0.001). Serum hCG, CA 125 and estradiol values were well correlated with adnexal mass size; for CA 125 this correlation was linear. There was no difference in serum biochemistry between hemodynamically stable and hemodynamically unstable women.

Conclusion: Common sonographic findings of tubal ectopic pregnancy do not correlate with serum biochemistry. High levels of CA 125, hCG or estradiol may suggest a larger adnexal mass in women with uncomplicated tubal pregnancies. Hemodynamically stable and hemodynamically unstable women do not differ in their serum biochemistry.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Biomarkers / blood
  • CA-125 Antigen / blood
  • Chorionic Gonadotropin / blood
  • Cohort Studies
  • Estradiol / blood
  • Female
  • Humans
  • Pregnancy
  • Pregnancy, Tubal / blood*
  • Pregnancy, Tubal / diagnostic imaging*
  • Progesterone / blood
  • Prospective Studies
  • Ultrasonography


  • Biomarkers
  • CA-125 Antigen
  • Chorionic Gonadotropin
  • Progesterone
  • Estradiol