Clinical significance of first trimester umbilical cord cysts.

A cystic mass of the umbilical cord was identified by transvaginal sonography in 10 first trimester pregnancies at a mean gestational age of 8 weeks 4 days (range, 8 weeks 1 day to 9 weeks 3 days) and at a mean crown-rump length of 20.5 mm (range, 15 to 25 mm). The cyst was solitary in all cases, the mean diameter was 4.6 mm (range, 3 to 6 mm), and the location was closer to the fetal insertion in two cases, in the middle of the cord in seven cases, and closer to the placental insertion in one case. Gestational sac and yolk sac diameters as well as the fetal heart rate were within normal ranges for gestational age in all cases. Information on detailed second trimester scans was available in nine cases, demonstrating complete resolution of the cyst and normal fetal anatomic survey in each case. These nine pregnancies were followed to delivery, and normal healthy infants were delivered at term in all cases. This series suggests that the incidental detection of umbilical cord cysts in early pregnancy is not associated with an adverse pregnancy outcome.