An anomaly scan takes a close look at your baby and your womb (uterus) at about 20 weeks of pregnancy. The person carrying out the scan (sonographer) will check that your baby is developing normally.
This ultrasound scan is very accurate but unfortunately it cannot diagnose 100% of congenital abnormalities. If the scan is complete, we would expect to pick up at least 95% of cases of spina bifida, 80% of cases of cleft lip or palate, and 60% to 70% of cases of congenital heart disease.
This scan can also identify 50% to 70% of cases of Down syndrome, but only an amniocentesis can give you this information for certain. It is also important to realise that ultrasound scans in pregnancy do not detect problems like cerebral palsy or autism.
Sometimes babies with chromosomal abnormalities have signs called ultrasound markers. These include thick skin in the neck, excess fluid in the kidneys, short arms or legs, white spots in the baby’s heart or abdomen, or choroid plexus cysts in the brain.
While some babies with chromosomal abnormalities have these markers, it is important to remember that many normal babies also have these signs. If the scan suggests a problem, you will be told this immediately. You will be able to discuss the findings immediately with a consultant who specialises in fetal medicine.
The only way to diagnose or exclude a chromosomal problem for certain is to have an amniocentesis. If you would prefer not to know about these markers please inform us prior to the scan.
A full support service will be available for you should any issue be detected, including a referral to an appropriate pediatrician. A copy of your report will be sent to your referring hospital, doctor or midwife to ensure good communication.