A detailed scan or an anomaly scan is an ultrasound examination done to look at the anatomical or physical structure of the baby. It can be a diagnostic test to check the physical structure or abnormalities in the baby.
It can also be used to screen for chromosomal abnormalities, but this will then require a diagnostic test such as amniocentesis. During the test, we look for soft markers that are not real abnormalities, but to show an increased risk of chromosomal abnormalities.
It is recommended to be done between 18 to 22 weeks of pregnancy. However, with better training and machines, most of the major abnormalities can be detected at 14 weeks of pregnancy but it is still recommended to repeat at 18 to 22 weeks of pregnancy especially in the heart where only about 50% of abnormalities can be detected in the best hands.
Here the whole structure of the baby that includes the head, brain, face chest, heart, stomach, kidneys, bladder, spine and all four limbs are checked to be anatomically normal.
This scan is best done by a maternal fetal medicine specialist. However, an obstetrician and gynaecologist that is trained and credentialled can also do these scans.
