What is detailed scan in pregnancy?

Detailed scan is also known as detailed anomaly scan or foetal anomaly scan. What is anomaly? It means not normal or abnormal.  So, a detailed scan in pregnancy is used to find out if your baby has any abnormal organ or body structure. The sonographer will look at your baby’s organs and body structures in more detail compared to basic ultrasound scan. Detailed scan is best performed when you are in 18 to 28 weeks of pregnancy.

However, you need to know that detailed scan can only detect structural abnormalities in 90% of cases. Examples of abnormalities are holes in the heart, deformed lips or shortened legs and arms. The scan also cannot detect if your baby has chromosomal abnormalities that do not display recognisable abnormal structures.

Do I need a detailed scan?

You will be advised for detailed scan if you have high risks of carrying a baby with abnormalities. Having said that, I actually recommend all pregnant women to have detailed scan. This is because a woman with no risk might still carry a baby with abnormalities. So, a detailed scan is an easy way to be more certain of your baby’s condition.

Below are the risks of carrying a baby with abnormalities:

  • Mother’s age more than 40 years old
  • Known diabetes mellitus before pregnancy
  • Known hypertension before pregnancy
  • Previous baby with structural or chromosomal abnormalities
  • Family history of structural or chromosomal abnormalities
  • Mother has congenital heart disease
  • Too little amniotic fluid (oligohydramnios)
  • Too much amniotic fluid (polyhydramnios)
  • Abnormal baby growth found on basic ultrasound scan
  • Abnormal results from chromosomal studies

In summary, I highly recommend detailed anomaly scan to all pregnant women. This is especially so if the woman has high risk of carrying a baby with abnormalities. If the detailed scan detects any abnormality, the doctor will discuss with you what to do next. So, if you are pregnant and wish for more information, do consult a doctor or sonographer. We will discuss with you in details on detailed scan.