velamentous insertion
Pronunciation: vel-ah-MEN-tus
Abnormal umbilical cord insertion where vessels run through fetal membranes before reaching the placenta.
Full Definition
Velamentous insertion is a placental abnormality where the umbilical cord inserts into the fetal membranes rather than directly into the placental disc. The umbilical vessels then travel unprotected through the membranes before reaching the placenta. This condition occurs in about 1% of singleton pregnancies and up to 15% of multiple pregnancies. The unprotected vessels are vulnerable to compression or rupture, particularly if they cross over the cervical opening (vasa previa). Velamentous insertion is associated with increased risks of intrauterine growth restriction, preterm delivery, and fetal bleeding. Diagnosis is typically made through ultrasound examination during pregnancy.
Usage
Usage note: Often associated with vasa previa when vessels cross the cervical opening.
In Context
- "Prenatal ultrasound identified velamentous insertion of the umbilical cord with vessels crossing the internal os." — Obstetric ultrasound report
- "The velamentous insertion was associated with intrauterine growth restriction in this pregnancy." — High-risk pregnancy consultation