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Umbilical Cord Abnormalities

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KEY POINTS
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Key Points

  • A variety of umbilical cord abnormalities may be sonographically detected, including short cord, lack of coiling, and cystic and vascular malformations.

  • Sonographic examination of the cord should include counting the number of vessels, Doppler studies, notation of coiling, and observation of the presence of cysts, masses, and vascular malformations.

  • Umbilical cord diameter increases with age.

  • The major consideration in the differential diagnosis is to determine if cord abnormality is isolated or associated with anomalies or aneuploidy.

  • The umbilical cord grows by tension generated by fetal movement. Short cords are associated with trisomy 21 and neuromuscular abnormalities.

  • Other findings associated with aneuploidy include lack of coiling, umbilical vein varix, aneurysms, and pseudocysts. Abnormal umbilical cord diameter measurements are not currently thought to be accurate markers of aneuploidy.

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CONDITION
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A variety of umbilical cord abnormalities may be detected by prenatal sonography. These conditions include a short cord, lack of coiling, umbilical cord ulceration, a knot in the umbilical cord, umbilical artery hypoplasia, supernumerary vessels, and a variety of cystic and vascular malformations (Table 108-1) (Persutte and Hobbins, 1995). The most common abnormality, single umbilical artery, is discussed in Chapter 109.

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Table Graphic Jump Location
Table 108-1Abnormalities of the Umbilical Cord
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INCIDENCE
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An absolutely short cord (<35 cm at term) occurs in 0.78% of pregnancies (Skupski et al., 1992). A relatively short cord (<54 cm at term) occurs in 16.8% of pregnancies (Skupski et al., 1992). Noncoiled umbilical vessels occur in 4.3% (38of 394 pregnancies) (Strong et al., 1993). Umbilical cord ulceration is a rare abnormality. Four umbilical vessels have been notedin 0.4% (2 of 444 pregnancies) (Aokio et al., 1997). Umbilical artery hypoplasia occurs in 1.9% of pregnancies (6 of 310 high-risk patients) (Sepulveda et al., 1992). A knot occurs in the umbilical cord in 0.3% to 2.1% of pregnancies (Sepulveda et al., 1995). Vascular malformations are rare. Tumors of the umbilical cord are extremely rare.

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SONOGRAPHIC FINDINGS
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Sonographic examination of the umbilical cord includes documentation of the number of vessels, Doppler velocimetry studies, and observation of coiling and looping of the cord (Figure 108-1). The umbilical cord is routinely examined in three locations: at the insertion site in the anterior abdominal wall of ...

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