Vasa praevia

Last revised by Maulik S Patel on 6 Aug 2023

Citation, DOI, disclosures and article data

Citation:

Weerakkody Y, Patel M, Yap J, et al. Vasa praevia. Reference article, Radiopaedia.org (Accessed on 23 Apr 2024) https://doi.org/10.53347/rID-13131

DOI:

https://doi.org/10.53347/rID-13131

Permalink:

https://radiopaedia.org/articles/13131

rID:

13131

Article created:

5 Mar 2011, Yuranga Weerakkody ◉

Disclosures:

At the time the article was created Yuranga Weerakkody had no recorded disclosures.

View Yuranga Weerakkody's current disclosures

Last revised:

6 Aug 2023, Maulik S Patel

Disclosures:

At the time the article was last revised Maulik S Patel had no financial relationships to ineligible companies to disclose.

View Maulik S Patel's current disclosures

Revisions:

21 times, by 15 contributors - see full revision history and disclosures

Systems:

Obstetrics

Tags:

placenta, obstetric, ultrasound

Synonyms:

Vasa previa

Vasa praevia refers to a situation where there are aberrant fetal vessels crossing over or in close proximity to the internal cervical os, ahead of the fetal presenting part. These vessels are within the amniotic membranes, without the support of the placenta. Vasa praevia is a rare but potentially catastrophic cause of antepartum haemorrhage.

type I (~90% ³): abnormal fetal vessels connect a velamentous cord insertion with the main body of the placenta
type II
- abnormal vessels connect portions of a bilobed placenta
- placenta with a succenturiate lobe: due to this association, vasa praevia needs to be excluded in patients with variant placental morphology

These vessels are unsupported by Wharton jelly or placental tissue and are at risk of rupture during labour.

Radiographic features

Ultrasound

Sonographic features are considered generally specific (~90%) ².

The diagnosis is often made with transabdominal colour Doppler sonography demonstrating flow within vessels that are seen overlying the internal cervical os. Greyscale images may suggest the diagnosis if there are echogenic parallel or circular lines within the placenta near the cervix.

Occasionally a transvaginal scan is required to better visualise aberrant vessels. Transvaginal ultrasound has a reported sensitivity of 100% and specificity of 99-99.8% when performed with colour Doppler ¹².

Treatment and prognosis

If recognised antenatally, vasa praevia usually requires an elective caesarean section to avoid the risk of complications during vaginal delivery.

If recognised intrapartum, an emergency caesarean section is usually performed.

Differential diagnosis

On antenatal ultrasound consider:

marginal placenta praevia: where prominent maternal vessels are appreciated at the edge of the placenta
funic presentation

References

1. Fadl S, Moshiri M, Fligner CL, Katz DS, Dighe M. Placental Imaging: Normal Appearance with Review of Pathologic Findings. Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (3): 979-998. doi:10.1148/rg.2017160155 - Pubmed
2. Catanzarite V, Maida C, Thomas W et-al. Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcome in ten cases. Ultrasound Obstet Gynecol. 2001;18 (2): 109-15. doi:10.1046/j.1469-0705.2001.00448.x - Pubmed citation
3. Hasegawa J, Farina A, Nakamura M et-al. Analysis of the ultrasonographic findings predictive of vasa previa. Prenat. Diagn. 2010;30 (12-13): 1121-5. doi:10.1002/pd.2618 - Pubmed citation
4. Lee W, Lee VL, Kirk JS et-al. Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. Obstet Gynecol. 2000;95 (4): 572-6. - Pubmed citation
5. Hertzberg BS, Kliewer MA. Vasa previa: prenatal diagnosis by transperineal sonography with Doppler evaluation. J Clin Ultrasound. 1998;26 (8): 405-8. J Clin Ultrasound (link) - Pubmed citation
6. Nimmo MJ, Kinsella D, Andrews HS. MRI in pregnancy: the diagnosis of vasa previa by magnetic resonance imaging. Bristol Med Chir J. 1988;103 (2): 12. - Pubmed citation
7. Oyelese Y, Jha RC, Moxley MD et-al. Magnetic resonance imaging of vasa praevia. BJOG. 2003;110 (12): 1127-8. BJOG (link) - Pubmed citation
8. Gagnon R, Morin L, Bly S et-al. Guidelines for the management of vasa previa. J Obstet Gynaecol Can. 2009;31 (8): 748-60. - Pubmed citation
9. Bluth EI. Ultrasound, a practical approach to clinical problems. George Thieme Verlag. (2000) ISBN:0865778612. Read it at Google Books - Find it at Amazon
10 .Benson CB, Ultrasonography In Obstetrics And Gynocology, A Practical Approach.. Thieme. (2007) ISBN:1588906124. Read it at Google Books - Find it at Amazon
12. L Ruiter, N Kok, J Limpens, JB Derks, IM de Graaf, BWJ Mol, E Pajkrt. Incidence of and risk indicators for vasa praevia: a systematic review. (2016) BJOG: An International Journal of Obstetrics & Gynaecology. 123 (8): 1278. doi:10.1111/1471-0528.13829 - Pubmed
12. Ruiter L, Kok N, Limpens J, Derks JB, de Graaf IM, Mol BW, Pajkrt E. Systematic review of accuracy of ultrasound in the diagnosis of vasa previa. (2015) Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 45 (5): 516-22. doi:10.1002/uog.14752 - Pubmed

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