Atypical Presentation of Ectopic Pregnancy with β-hCG Rise Mimicking a Normal Intrauterine Pregnancy

Dr. Syeda Sana Ali*, Dr. Manal Ibrahim Sabbar¹, Dr. Ikran Adan²

1. MBChB, MRCOG, CABOG, Consultant Obstetrician and Gynecologist, Al Tadawi Specialty Hospital, Dubai, UAE.

2. MBChB, MRCOG, MSc (Obs/Gynae), Specialist Obstetrician and Gynecologist, Al Tadawi Specialty Hospital, Dubai, UAE.

*Correspondence to: Dr. Syeda Sana Ali, MBBS, FCPS, MRCOG, Fellowship in IVF and reproductive medicine, Specialist Obstetrician and Gynecologist, Al Tadawi Specialty Hospital, Dubai, UAE.

Copyright                          

© 2026 Dr. Syeda Sana Ali, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 06 January 2026

Published: 01 February 2026

DOI: https://doi.org/10.5281/zenodo.19366786

Abstract

Background: Ectopic pregnancy classically presents with a suboptimal β-hCG rise; however, normal-rise patterns may occur and mislead diagnosis.

Case: A 36-year-old woman presented at 5+2 weeks with rising β-hCG (1,166 → 2,043 mIU/mL; +85%/48h). At 6+4 weeks she developed mild pain and spotting. β-hCG was 19,000 mIU/mL but transvaginal ultrasound revealed an empty uterus and a right adnexal mass.

Laparoscopic salpingectomy confirmed ectopic pregnancy.

Conclusion: A normal β-hCG rise cannot exclude ectopic pregnancy. Ultrasound findings must take precedence over biochemical trends.

Introduction
Ectopic pregnancy remains a leading cause of first-trimester morbidity. Classically, diagnosis relies on discordance between β-hCG kinetics and ultrasound findings. However, approximately 8–10% of ectopic pregnancies demonstrate a normal β-hCG rise, creating a false sense of reassurance. Such atypical patterns may delay diagnosis, increasing risk of rupture and haemorrhage. This case highlights the diagnostic challenge posed by normal β-hCG dynamics and reinforces the importance of correlating symptoms with imaging.

Case Presentation

A 36-year-old primigravida presented at 5+2 weeks with a positive pregnancy test. She denied pain or bleeding. Initial β-hCG was 1,166 mIU/mL. At 5+4 weeks, β-hCG rose to 2,043 mIU/mL (+85% in 48 hours). At 6+4 weeks she developed mild right-sided pelvic pain and brownish spotting. β-hCG had increased to 19,000 mIU/mL. Transvaginal ultrasound revealed an empty uterus despite β-hCG exceeding the discriminatory zone. A right adnexal cystic lesion (9.5×8.5 mm) adjacent to a 3.5 cm ovarian cyst was noted. Minimal free fluid was present. She underwent laparoscopic salpingectomy, confirming a right tubal ectopic pregnancy.

Discussion

Although a suboptimal β-hCG rise is characteristic of ectopic pregnancy, up to 10% may show normal doubling. Therefore, biochemical trends alone cannot exclude ectopic implantation. When β-hCG exceeds the discriminatory zone without visualization of an intrauterine gestational sac, ectopic pregnancy must be strongly suspected. Early imaging is crucial. This case reinforces that ultrasound findings should take precedence when discordant with biochemical parameters.

Differential Diagnosis

-Viable intrauterine pregnancy

-Pregnancy of unknown location

-Early pregnancy loss

-Ovarian cyst / corpus luteum cyst

-Ovarian torsion

-Appendicitis

Management

The patient underwent laparoscopic right salpingectomy due to high β-hCG levels, presence of adnexal mass, and symptoms. Intraoperative findings confirmed tubal ectopic pregnancy.

Outcome and Follow-Up

Recovery was uneventful. She was discharged with advice for serial β-hCG monitoring and early ultrasound in future pregnancies.

Limitations

- Serum progesterone was not assessed.

- Left ovary was not visualized.

- Early ultrasound at 5 weeks was not performed.

Conclusion

A normal β-hCG rise cannot reliably exclude ectopic pregnancy. When ultrasound and β-hCG trends disagree, imaging findings hold greater diagnostic value.

References

1. Barnhart KT. Ectopic pregnancy. N Engl J Med. 2009.
2. Seeber BE. What serial hCG can tell you. Obstet Gynecol. 2012.
3. ACOG Practice Bulletin: Tubal Ectopic Pregnancy. 2018.
4. NICE Guideline NG126: Ectopic Pregnancy and Miscarriage. 2019.
5. Morse CB et al. β-hCG rise in ectopic pregnancy. Obstet Gynecol. 2012.
6. Condous G. Pregnancy of unknown location. Best Pract Res Clin Obstet Gynaecol. 2013.
7. RCOG Green-top Guideline 21. 2016.
8. Kadar N. Discriminatory β-hCG zone. Fertil Steril. 1981.
9. Kirk E. Role of ultrasound in ectopic pregnancy. Ultrasound Obstet Gynecol. 2007.
10. Doubilet PM. Diagnostic pitfalls in early pregnancy. Radiology. 2014.