Velamentous insertion of the umbilical cord: a first-trimester sonographic screening study.

OBJECTIVE: The purpose of this study was to determine the feasibility of prenatal sonography for detecting velamentous insertion of the umbilical cord in singleton pregnancies at the 11- to 14-week scan.

METHODS: The placental umbilical cord insertion site was prospectively examined at the time of the routine first-trimester scan between 11 and 14 weeks as part of ongoing first-trimester sonographic screening for chromosomal abnormalities.

RESULTS: Over a 1-year period, 533 consecutive singleton pregnancies were examined by a fetal medicine specialist at a median gestational age of 12 weeks. In 5 cases, a velamentous umbilical cord insertion was diagnosed, with a prevalence rate of 1 (0.9%) per 107. The diagnosis was further confirmed at the second-trimester scan and at the time of delivery in all cases.

CONCLUSIONS: The placental umbilical cord insertion site can be readily determined by sonography at the time of the 11- to 14-week scan. Sonographic examination at this early gestational age provides the opportunity for screening for velamentous insertion of the umbilical cord in the first trimester, allowing close surveillance of the pregnancy for potential complications associated with this condition.