An ultrasound marker is the name given to any physical sign in the baby, umbilical cord or placenta that has been associated with an abnormality in the baby or a complication of pregnancy. The ultrasound marker can be present or absent in order to alert the scanner to a potential problem. For example the absence of a nasal bone has been associated with Down’s syndrome and so too has the presence of increased fluid under the skin behind the neck of the fetus at 11 to 13 weeks’ gestation (nuchal translucency screening, or NTS) and the presence of a single palmar crease on the hands.
It is important to remember that a normal anomaly scan during pregnancy does not guarantee that your baby will not have a problem. About two-thirds of recognised syndromes have been associated with structural markers but there are no established antenatal markers for conditions such as mental retardation or cerebral palsy. Some structural abnormalities may be present in early pregnancy and give rise to concerns, only to disappear later on in pregnany. Choroid plexus cysts and enlarged kidneys are good examples – they are usually insignificant but in some cases are associated with chromosomal abnormalities. Detailed counselling will be needed to help parents decide whether they should expose their baby to the risk of an invasive diagnostic test when an ultrasound marker is identified.
Now tell us what happened to you…
Did you have an ultrasound marker? How did it affect your pregnancy?