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2017-05-15  Circumvallate placenta  © Islam Badr

Circumvallate placenta
Islam Badr, M.Sc.*; Rasha Kamel, MD*; Sameh Abdel Latif Abdel Salam, MD***
 * Fetal medicine unit, Cairo University, Egypt;
** Radiology department, Kasr Alainy teaching hospitals, Cairo University, Egypt.

Fusion of fetal amniotic membranes medially in relation to the chorionic plate true edge leads to the formation of a placental shelf which should put circumvallate placenta in the differential diagnosis1. This will lead to elevated or rolled-up placental edge. This placental shelf should not attach to any part of the fetus and should have a free edge projecting into the uterine cavity 2,3. In cases of circumvallate placenta, this shelf may be only apparent in second trimester but not in the third trimester when only a bright border at the edge of the placenta may be noticed3. Sub-amniotic anechoic areas are seen in some cases of circumvallate placenta3 and according to some authors, they represent an important clue to the diagnosis4. There is ongoing debate about the significance of the circumvallate placenta; some refer to it as an anatomic variant4 however recently some reports of increased risk of adverse outcome have been published5.

Case report

A 29 year old pregnant woman presented to us at 23 weeks gestation for routine ultrasound study. Our ultrasound examination revealed the presence of circumvallate placenta.

Images 1-6 and Videos 1, 2: show the discrepancy between the basal and the chorionic plates, the rolled-up placenta edges (shelf) and the marginal sub-amniotic anechoic areas. 



1. Rheinboldt M,  Delproposto. Sonography of placental abnormalities: a pictorial review. Emerg Radiol 2015; 22:401-408.
2. Shen O, Golobm E, Lavie O, Goldberg Y, Eitan R, Rabinowitz RR. Placental shelf - a common, typically transient and benign finding on early second-trimester sonography. Ultrasound Obstet Gynecol 2007; 29:192-194.
3- McCarthy J, Thurmond AS, Jones MK, Sistrom C, Scanlan RM, Jacobson SL, Lowensohn R. Circumvallate Placenta: Sonographic Diagnosis. J Ultrasound Med 1995; 14:21-26.

4- Bey M, Dott A, Miller JM. The sonographic diagnosis of circumvallate placenta. Obstet Gynecol 1991; 78: 515-517.

5- Taniguchi H, Aoki S, Sakamaki K, Kurasawa K, Okuda M, Takahashi T, Hirahara F. Circumvallate placenta: associated clinical manifestations and complications – A retrospective study. Obstet Gynecol Int. 2014;2014:986230. doi:
10.1155/2014/986230. Epub 2014 Nov13.

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