Smarter Decisions,
Better Care

UpToDate synthesizes the most recent medical information into evidence-based practical recommendations clinicians trust to make the right point-of-care decisions.

  • Rigorous editorial process: Evidence-based treatment recommendations
  • World-Renowned physician authors: over 5,100 physician authors and editors around the globe
  • Innovative technology: integrates into the workflow; access from EMRs

Choose from the list below to learn more about subscriptions for a:


Subscribers log in here


Velamentous umbilical cord insertion and vasa previa

INTRODUCTION

A velamentous umbilical cord is characterized by membranous umbilical vessels at the placental insertion site; the remainder of the cord is usually normal. Membranous vessels can also arise as aberrant branches of a marginally inserted umbilical cord or they can connect lobes of a bilobed placenta or the placenta and a succenturiate lobe. Because of the lack of protection from Wharton’s jelly, these vessels are prone to compression and rupture, especially when they are located in the membranes covering the cervical os (ie, vasa previa).

VELAMENTOUS UMBILICAL CORD

Definition — In a velamentous umbilical cord insertion, the placental end of the cord consists of divergent umbilical vessels surrounded only by fetal membranes, with no Wharton's jelly. The length of the membranous vessels, ie, the distance between the end of the normal cord and the placental insertion, is highly variable.

Prevalence — Velamentous insertion occurs in approximately 1 percent of singleton gestations [1], but is observed in as many as 15 percent of monochorionic twin gestations [2-4]. It is also more common in placenta previa than in normally located placentas. The prevalence may be slightly higher in stillbirths, particularly from multifetal pregnancies [4].

Pathogenesis — The pathogenesis of velamentous cord insertion is unknown. The most popular hypothesis is that the cord is initially inserted centrally, but its location progressively becomes peripheral as one half of the placenta actively proliferates toward the well-vascularized uterine fundus (trophotropism) while the other pole involutes; the umbilical cord is unable to follow the migration of the placenta [5]. The association of velamentous cord insertion and placenta previa supports this hypothesis.

Clinical features

Ultrasound and gross examination — On ultrasound and gross examination, the normal umbilical cord sheath is contiguous with the chorionic plate. With a velamentous insertion, the cord can end several centimeters from the placenta, at which point the umbilical vessels separate from each other and cross between the amnion and chorion before connecting to the subchorionic vessels of the placenta (picture 1A-C). This typically occurs at the margin of the placenta (within 1 cm of the placental edge), but can also occur at the apex of the gestational sac. In monochorionic twins, the velamentous vessels often occur in the dividing membranes.

                     

Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Oct 2014. | This topic last updated: Jan 6, 2014.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2014 UpToDate, Inc.
References
Top
  1. Sepulveda W, Rojas I, Robert JA, et al. Prenatal detection of velamentous insertion of the umbilical cord: a prospective color Doppler ultrasound study. Ultrasound Obstet Gynecol 2003; 21:564.
  2. Lopriore E, Sueters M, Middeldorp JM, et al. Velamentous cord insertion and unequal placental territories in monochorionic twins with and without twin-to-twin-transfusion syndrome. Am J Obstet Gynecol 2007; 196:159.e1.
  3. Kent EM, Breathnach FM, Gillan JE, et al. Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective ESPRiT Study. Am J Obstet Gynecol 2011; 205:376.e1.
  4. Pinar H, Carpenter M. Placenta and umbilical cord abnormalities seen with stillbirth. Clin Obstet Gynecol 2010; 53:656.
  5. Kouyoumdjian A. Velamentous insertion of the umbilical cord. Obstet Gynecol 1980; 56:737.
  6. Hasegawa J, Matsuoka R, Ichizuka K, et al. Ultrasound diagnosis and management of umbilical cord abnormalities. Taiwan J Obstet Gynecol 2009; 48:23.
  7. BILEK K, ROTHE K, PICKAZECK K. [Hemorrhage of the velamentous insertion before rupture of the membranes]. Zentralbl Gynakol 1962; 84:1536.
  8. Hoyme HE, Jones KL, Van Allen MI, et al. Vascular pathogenesis of transverse limb reduction defects. J Pediatr 1982; 101:839.
  9. Williams JH, Benirschke K. Chorionic vessel thrombosis: a possible etiology of neonatal purpura. J Reprod Med 1978; 20:285.
  10. Eddleman KA, Lockwood CJ, Berkowitz GS, et al. Clinical significance and sonographic diagnosis of velamentous umbilical cord insertion. Am J Perinatol 1992; 9:123.
  11. Benirschke, K, Kaufmann, P. Pathology of the Human Placenta. New York, NY: Springer-Verlag, 2000; 353.
  12. Sepulveda, W, Sebire, NJ, Harris, R, Nyberg, DA. The placenta, umbilical cord, and membranes. In: Diagnostic Imaging of Fetal Anomalies, Nyberg DA , McGrahan JP , Pretorius DH , Pilu G (eds). Lippincott Williams & Wilkins: Philadelphia, 2003; 85.
  13. Robinson LK, Jones KL, Benirschke K. The nature of structural defects associated with velamentous and marginal insertion of the umbilical cord. Am J Obstet Gynecol 1983; 146:191.
  14. Bjøro K Jr. Vascular anomalies of the umbilical cord: I. Obstetric implications. Early Hum Dev 1983; 8:119.
  15. Heinonen S, Ryynänen M, Kirkinen P, Saarikoski S. Perinatal diagnostic evaluation of velamentous umbilical cord insertion: clinical, Doppler, and ultrasonic findings. Obstet Gynecol 1996; 87:112.
  16. Yampolsky M, Salafia CM, Shlakhter O, et al. Centrality of the umbilical cord insertion in a human placenta influences the placental efficiency. Placenta 2009; 30:1058.
  17. Uyanwah-Akpom P, Fox H. The clinical significance of marginal and velamentous insertion of the cord. Br J Obstet Gynaecol 1977; 84:941.
  18. Woods DL, Malan AF. The site of umbilical cord insertion and birth weight. Br J Obstet Gynaecol 1978; 85:332.
  19. De Paepe ME, Shapiro S, Young L, Luks FI. Placental characteristics of selective birth weight discordance in diamniotic-monochorionic twin gestations. Placenta 2010; 31:380.
  20. Monteagudo A, Sfakianaki AK, Timor-Tritsch IE. Velamentous insertion of the cord in the first trimester. Ultrasound Obstet Gynecol 2000; 16:498.
  21. http://www.acr.org/SecondaryMainMenuCategories/quality_safety/guidelines/us/us_obstetrical.aspx (Accessed on February 08, 2012).
  22. 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; 18:109.
  23. Lee W, Lee VL, Kirk JS, et al. Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. Obstet Gynecol 2000; 95:572.
  24. Francois, K, Mayer, S, Harris, C, Perlow, JH. Association of vasa previa at delivery with a history of second-trimester placenta previa. Obstetrical & Gynecological Survey 2004; 59:245.
  25. Bronsteen R, Whitten A, Balasubramanian M, et al. Vasa previa: clinical presentations, outcomes, and implications for management. Obstet Gynecol 2013; 122:352.
  26. Oyelese Y, Spong C, Fernandez MA, McLaren RA. Second trimester low-lying placenta and in-vitro fertilization? Exclude vasa previa. J Matern Fetal Med 2000; 9:370.
  27. Schachter M, Tovbin Y, Arieli S, et al. In vitro fertilization is a risk factor for vasa previa. Fertil Steril 2002; 78:642.
  28. Baulies S, Maiz N, Muñoz A, et al. Prenatal ultrasound diagnosis of vasa praevia and analysis of risk factors. Prenat Diagn 2007; 27:595.
  29. Al-Khaduri M, Kadoch IJ, Couturier B, et al. Vasa praevia after IVF: should there be guidelines? Report of two cases and literature review. Reprod Biomed Online 2007; 14:372.
  30. Hasegawa J, Farina A, Nakamura M, et al. Analysis of the ultrasonographic findings predictive of vasa previa. Prenat Diagn 2010; 30:1121.
  31. Lijoi AF, Brady J. Vasa previa diagnosis and management. J Am Board Fam Pract 2003; 16:543.
  32. Rebarber A, Dolin C, Fox NS, et al. Natural history of vasa previa across gestation using a screening protocol. J Ultrasound Med 2014; 33:141.
  33. Antoine C, Young BK, Silverman F, et al. Sinusoidal fetal heart rate pattern with vasa previa in twin pregnancy. J Reprod Med 1982; 27:295.
  34. Nguyen D, Nguyen C, Yacobozzi M, et al. Imaging of the placenta with pathologic correlation. Semin Ultrasound CT MR 2012; 33:65.
  35. Kikuchi A, Uemura R, Serikawa T, et al. Clinical significances of magnetic resonance imaging in prenatal diagnosis of vasa previa in a woman with bilobed placentas. J Obstet Gynaecol Res 2011; 37:75.
  36. Nimmo MJ, Kinsella D, Andrews HS. MRI in pregnancy: the diagnosis of vasa previa by magnetic resonance imaging. Bristol Med Chir J 1988; 103:12.
  37. Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol 2006; 107:927.
  38. Mabuchi Y, Yamoto M, Minami S, et al. Two cases of vasa previa diagnosed prenatally using three-dimensional ultrasonography. J Clin Ultrasound 2010; 38:389.
  39. Araujo Júnior E, Filho HA, Pires CR, et al. Prenatal diagnosis of vasa previa through color Doppler and three-dimensional power Doppler ultrasonography. A case report. Clin Exp Obstet Gynecol 2006; 33:122.
  40. Canterino JC, Mondestin-Sorrentino M, Muench MV, et al. Vasa previa: prenatal diagnosis and evaluation with 3-dimensional sonography and power angiography. J Ultrasound Med 2005; 24:721.
  41. Oyelese Y, Chavez MR, Yeo L, et al. Three-dimensional sonographic diagnosis of vasa previa. Ultrasound Obstet Gynecol 2004; 24:211.
  42. Odunsi K, Bullough CH, Henzel J, Polanska A. Evaluation of chemical tests for fetal bleeding from vasa previa. Int J Gynaecol Obstet 1996; 55:207.
  43. Kumazawa Y, Shimizu D, Hosoya N, et al. Cervical varix with placenta previa totalis. J Obstet Gynaecol Res 2007; 33:536.
  44. Kusanovic JP, Soto E, Espinoza J, et al. Cervical varix as a cause of vaginal bleeding during pregnancy: prenatal diagnosis by color Doppler ultrasonography. J Ultrasound Med 2006; 25:545.
  45. Hurton T, Morrill H, Mascola M, et al. Cervical varices: an unusual etiology for third-trimester bleeding. J Clin Ultrasound 1998; 26:317.
  46. Gagnon R, Morin L, Bly S, et al. Guidelines for the management of vasa previa. J Obstet Gynaecol Can 2009; 31:748.
  47. Cipriano LE, Barth WH Jr, Zaric GS. The cost-effectiveness of targeted or universal screening for vasa praevia at 18-20 weeks of gestation in Ontario. BJOG 2010; 117:1108.
  48. Oyelese Y, Catanzarite V, Prefumo F, et al. Vasa previa: the impact of prenatal diagnosis on outcomes. Obstet Gynecol 2004; 103:937.
  49. Robinson BK, Grobman WA. Effectiveness of timing strategies for delivery of individuals with vasa previa. Obstet Gynecol 2011; 117:542.