Citation, DOI & article data
A pseudogestational sac, also known as a pseudosac or intra-cavitary fluid, is the concept that a small amount of intrauterine fluid in the setting of a positive pregnancy test and abdominal pain could be erroneously interpreted as a true gestational sac in ectopic pregnancy.
The sign was originally reported before the use of transvaginal ultrasound imaging and caution should be exercised if considering diagnosing a pseudogestational sac with modern ultrasound equipment. In a woman with a positive beta-hCG, any intrauterine sac-like fluid collection seen on ultrasound is highly likely to be a gestational sac 6.
- generally irregularly-shaped with pointed edges and/or filled with debris, sometimes referred to as 'beaking'
- centrally located in the endometrial cavity, rather than eccentrically located within the endometrium
- displaces the anterior and posterior endometrial cavity surfaces
- does not demonstrate a yolk sac
- a double decidual layer is compatible with intrauterine pregnancy, but lack of this sign is not specific for pseudogestational sac
- may be surrounded by a thick decidual layer
The idea of beta-hCG "discriminatory levels" has also fallen out of favor since this sign was formulated. Caution should be exercised in making a diagnosis of pseudogestational sac based on a beta-HCG level at which a yolk sac is expected to be seen as this has been shown to be unreliable. Therapy should not be initiated in a haemodynamically-stable woman on the basis of a single beta-hCG level.
- 1. Weissleder R, Wittenberg J, Harisinghani MM et-al. Primer of Diagnostic Imaging, Expert Consult- Online and Print. Mosby. (2011) ISBN:0323065384. Read it at Google Books - Find it at Amazon
- 2. Chudleigh P, Thilaganathan B. Obstetric ultrasound, how, why and when. Churchill Livingstone. (2004) ISBN:0443054711. Read it at Google Books - Find it at Amazon
- 3. N Gupta and TL Angtuaco "Embryosonology in the First Trimester of Pregnancy" Ultrasound Clinics 2 (2007) 175-185
- 4. Chiang G, Levine D, Swire M et-al. The intradecidual sign: is it reliable for diagnosis of early intrauterine pregnancy? AJR Am J Roentgenol. 2004;183 (3): 725-31. AJR Am J Roentgenol (full text) - Pubmed citation
- 5. Kaakaji Y, Nghiem HV, Nodell C et-al. Sonography of obstetric and gynecologic emergencies: Part I, Obstetric emergencies. AJR Am J Roentgenol. 2000;174 (3): 641-9. AJR Am J Roentgenol (full text) - Pubmed citation
- 6. Doubilet PM. Ultrasound Evaluation of the First Trimester. Radiol. Clin. North Am. 2014;52 (6): 1191-1199. doi:10.1016/j.rcl.2014.07.004 - Pubmed citation
- 7. Doubilet PM, Benson CB. Further evidence against the reliability of the human chorionic gonadotropin discriminatory level. J Ultrasound Med. 2012;30 (12): 1637-42. Pubmed citation
- 8. Karen Mizia, Sue Campbell Westerway, Meiri Robertson, Emma Parry, Debra Paoletti, David Perry, Jayshree Ramkrishna, Lyndal Macpherson, George Condous. Guidelines for the performance of the first trimester ultrasound. (2018) Australasian Journal of Ultrasound in Medicine. 21 (3): 179. doi:10.1002/ajum.12102 - Pubmed
- 9. Connolly A, Ryan DH, Stuebe AM, Wolfe HM. Reevaluation of discriminatory and threshold levels for serum β-hCG in early pregnancy. (2013) Obstetrics and gynecology. 121 (1): 65-70. doi:10.1097/aog.0b013e318278f421 - Pubmed