Prenatal Ultrasound Scanning Recommended for Vasa Praevia

A new study reviewed the mechanisms leading to a medical condition related to childbirth, called vasa praevia (VP), as well as the incidence, clinical implications, and risk factors associated with this condition, and recommended routine evaluation to exclude VP in all routine obstetric scans as a matter of urgency.

Vasa Praevia is a condition that affects approximately 1 in 2,500 deliveries, and as many as 1 in 300 in in-vitro fertilization (IVF) pregnancies. The researchers of the study believe that it is important to persuade all those undertaking the detailed anomaly scan that excluding VP is a worthwhile endeavor and one that is easily achievable within the confines of the second-trimester anomaly ultrasound scan.

Vasa praevia occurs when one or more of the baby's placental or umbilical blood vessels cross the entrance to the birth canal beneath the baby. When the cervix dilates or the membranes rupture, the unprotected vessels can tear, causing rapid fetal hemorrhage. When the baby drops into the pelvis, the vessels can be compressed, compromising the infant's blood supply and causing oxygen deprivation.

The study was published in the February 2008 issue of the journal Ultrasound, and the researchers included Dr. Elizabeth Daly-Jones and colleagues from the ultrasound department, Queen Charlotte's and Chelsea Hospital (London, UK), and Dr. Waldo Sepulveda from the Fetal Medicine Center, Clinica Las Condes (Santiago, Chile).

Dr. Daly-Jones hopes the study will raise awareness of VP in prenatal scans. "The method for excluding VP is a very simple technique, uses skills that trained practitioners already possess, and takes approximately a minute of extra examination time. VP is life-threatening to a healthy baby, but a proper diagnosis and an elective Caesarean section will easily prevent unnecessary deaths.”


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