Diagnostic Imaging Pathways - Ectopic Pregnancy (Suspected)
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This pathway provides guidance on the imaging of female patients presenting with suspected ectopic pregnancy.
Date reviewed: October 2013
Date of next review: 2017/2018
Published: November 2013
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SYMBOL | RRL | EFFECTIVE DOSE RANGE |
![]() | None | 0 |
![]() | Minimal | < 1 millisieverts |
![]() | Low | 1-5 mSv |
![]() | Medium | 5-10 mSv |
![]() | High | >10 mSv |
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Teaching Points
Teaching Points
- Transvaginal and abdominal US combined with the measurement of serum β-hCG are the investigations of choice for suspected ectopic pregnancy
- In a small proportion of cases the TVUS may be non-diagnostic. Follow up of these patients is dependant on the value of the quantitative β-hCG -
- A β-hCG > 1500 IU should proceed to laparoscopy
- A β-hCG < 1500 IU should be repeated in 48hrs if the patient is clinically stable, expecting a rise of > 66%
- A normal US does not exclude an ectopic pregnancy
hcg
Serum Human Chorionic Gonadotrophin (ß-hCG) Levels
- Levels of 1000-1500iu/l should be associated with the presence of an intrauterine gestation on transvaginal US (6000-6500 iu/l for transabdominal), although in multiple pregnancy this level may be higher 8
- Serum ß-hCG levels double approximately every 48 hours in 85% of normal intrauterine pregnancies of between 4 and 6 weeks' gestation 20
- 80% of ectopic pregnancies are associated with a rise in ß-hCG of less than 66% 19,20
us
Transabdominal +/- Transvaginal Ultrasonography
- Pelvic ultrasonography (transabdominal US +/- transvaginal US) combined with measurement of serum ß-hCG levels, is an effective screening strategy for diagnosing ectopic pregnancy 3-6
- Allows identification of an intrauterine pregnancy, which is the single most important finding for the exclusion of ectopic gestation as the presence of both intra- and extra-uterine pregnancy, is very rare 1,3-6
- Compared to transabdominal ultrasonography, transvaginal ultrasonography is more sensitive and has a lower discriminatory zone (the range of serum ß-hCG concentrations above which gestational sac can be visualised consistently). This allows earlier diagnoses of intrauterine or ectopic pregnancies 7-11
- Sensitivity for transvaginal ultrasonography ranges from 69 to 96% and specificity from 84 to 99% 1,3,9,12
- When used in conjunction with serum ß-hCG levels, transvaginal ultrasound has comparable sensitivity and specificity for ectopic pregnancy to laparoscopy 13
- Presence of an adnexal mass and/or free pelvic fluid is strong predictor of an ectopic pregnancy 10,14-17
- Findings suggestive of ectopic pregnancy include 13
- Fluid in the pouch of Douglas, an adnexal mass and an empty uterus
- An adnexal mass, empty uterus or pseudogestational sac and a positive ß-hCG
- Direct demonstration of ectopic fetus and fetal heart
- Normal US does not exclude the diagnosis of ectopic pregnancy 3,14,15
- Patients with indeterminate ultrasonography findings require further evaluation with quantitative ß-hCG levels +/- follow-up US or laparoscopy as about 15-20% of these patients will have a final diagnosis of ectopic pregnancy 18,19
References
References
Date of literature search: July 2013
The search methodology is available on request. Email
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Kaplan BC, Dart RG, Moskos M, et al. Ectopic pregnancy: prospective study with improved diagnostic accuracy. Ann Emerg Med. 1996;28:10-17. (Level II evidence) View the reference
- Abbott JT, Emmans LS, Lowenstein SR. Ectopic pregnancy: ten common pitfalls in diagnosis. Am J Emerg Med. 1990;8:515-22. (Level IV evidence)
- Braffman BH, Coleman BG, Ramchandani P, et al. Emergency department screening for ectopic pregnancy: a prospective US study. Radiology. 1994;190:797-802. (Level II evidence) View the reference
- Barnhart K, Mennuti MT, Benjamin I, et al. Prompt diagnosis of ectopic pregnancy in an emergency department setting. Obstet Gynecol. 1994;84:1010-5. (Level II evidence)
- Gracia CR, Barnhart KT. Diagnosing ectopic pregnancy: decision analysis comparing six strategies. Obstet Gynecol. 2001;97:464-70. (Level II evidence)
- Wong TW, Lau CC, Yeung A, et al. Efficacy of transabdominal ultrasound examination in the diagnosis of early pregnancy complications in an emergency department. J Accid Emerg Med. 1998;15:155-8. (Level II evidence) View the reference
- Jain KA, Hamper UM, Sanders RC. Comparison of transvaginal and transabdominal sonography in the detection of early pregnancy and its complications. AJR Am J Roentgenol. 1988;151:1139-43. (Level III evidence)
- Nyberg DA, Mack LA, Laing FC, et al. Early pregnancy complications: endovaginal sonographic findings correlated with human chorionic gonadotropin levels. Radiology. 1988;167:619-22. (Level III evidence)
- Nyberg DA, Mack LA, Jeffery RB Jr, et al. Endovaginal sonographic evaluation of ectopic pregnancy: a prospective study. AJR Am J Roentgenol. 1987;149:1181-6. (Level III evidence)
- Cacciatore B, Stenman UH, Ylostalo P. Diagnosis of ectopic pregnancy by vaginal ultrasonography in combination with a discriminatory serum hCG level of 1000 IU/l [IRP]. Br J Obstet Gynaecol. 1990;97:904-8. (Level II evidence) View the reference
- Cacciatore B, Stenman UH, Ylostalo P, et al. Comparison of abdominal and vaginal sonography in suspected ectopic pregnancy. Obstet Gynecol. 1989;73:770-4. (Level III evidence)
- Timor-Tritch IA, Yeh MN, Peisner DB, et al. The use of transvaginal ultrasonography in the diagnosis of ectopic pregnancy. Am J Obst Gynecol. 1989;161:157-61. (Level III evidence)
- Sadek AL, Schiotz HA. Transvaginal sonography in the management of ectopic pregnancy. Acta Obstet Gynecol Scand. 1995;74:293-6. (Level II evidence)
- Brown DL, Doubilet PM. Transvaginal sonography for diagnosing ectopic pregnancy: positivity criteria and performance characteristics. J Ultrasound Med 1994;13:259-66. (Level II evidence) View the reference
- Russell SA, Filly RA, Damato N. Sonographic diagnosis of ectopic pregnancy with endovaginal probes: what really has changed? J Ultrasound Med. 1993;3:145-51. (Level III evidence)
- Nyberg DA, Hughes MP, Mack LA, et al. Extrauterine findings of ectopic pregnancy at transvaginal US: importance of echogenic fluid. Radiology. 1991;178:823-6. (Level II evidence) View the reference
- Cacciatore B. Can the status of tubal pregnancy be predicted with transvaginal sonography? A prospective comparison of sonographic, surgical and serum hCG findings. Radiology. 1990;177:481-4. (Level II evidence) View the reference
- Dart RG, Burke G, Dart L. Subclassification of indeterminate pelvic ultrasonography: prospective evaluation of the risk of ectopic pregnancy. Ann Emer Med. 2002;39:382-8. (Level II evidence) View the reference
- Dart RG, Mitterando J, Dart LM. Rate of change of serial ß-human chorionic gonadotropin values as a predictor of ectopic pregnancy in patients with indeterminate transvaginal ultrasound findings. Ann Emerg Med. 1999;34:703-10. (Level II evidence) View the reference
- Symonds IM. Ectopic pregnancy: modern management. Current Obstetrics & Gynaecology. 1998;8:27-31. (Review article) View the reference
Further Reading
- Dart RG. Role of pelvic ultrasonography in evaluation of symptomatic first-trimester pregnancy. Ann Emerg Med. 1999;33:310-20. (Review article)
- Frates MC, Laing FC. Sonographic evaluation of ectopic pregnancy: an update. AJR Am J Roentgenol. 1995;165:251-9. (Review article)
- Durston WE, Carl ML, Guerra W, et al. Ultrasound availability in the evaluation of ectopic pregnancy in the ED: comparison of quality and cost-effectiveness with different approaches. Am J Emerg Med. 2000;18:408-17. (Level III evidence)
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Consent to Procedure or Treatment Radiation Risks of X-rays and Scans |
Radiation Risk of Medical Imaging During Pregnancy Radiation Risk of Medical Imaging for Adults and Children |
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