Umbilical cord cysts in early pregnancy.

Abstract

To assess the prevalence, morphologic characteristics, and natural history of umbilical cord cysts detected by ultrasound in the first trimester of pregnancy. This was an ultrasound screening study for the presence of umbilical cord cysts in 859 pregnant women with singleton live fetuses at 7-13 weeks' gestation. In all cases of cord cysts the scan was repeated fortnightly until the cyst resolved or a fetal abnormality was detected. All patients with ongoing pregnancies had detailed scans at 20 weeks. Infants and umbilical cords were examined after delivery for the presence of structural abnormalities. Umbilical cord cysts were present in 29 (3.4%) of the 859 pregnancies. Fetal abnormalities were found in seven (26%) of the 27 cases with ongoing pregnancies. The fetus was more likely to be abnormal if the cyst was located near the placental or fetal extremity of the cord (relative risk [RR] 3.3; 95% confidence interval [CI] 1.3, 8.5) or paraxially (RR 3.8; 95% CI 1.2, 12.0) or if it persisted beyond 12 weeks' gestation (RR 7.7; 95% CI 3.2, 18.6). The prevalence of umbilical cord cysts at 7-13 weeks' gestation is approximately 3%, and in more than 20% of cases there are fetal chromosomal or structural defects.