Anomaly Scan in Pregnancy

Images of an ultrasound anomaly scan on a foetus, 20 weeks into pregnancy

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There are three trimesters in pregnancy and each trimester holds its importance in the birth cycle of a child. It is essential to get various scans and health check-ups performed during the nine month period to ensure that the baby’s growth is normal and on track. An anomaly test or scan is conducted in the second trimester of pregnancy predominantly to track the growth progress of the foetus.





During the scan, the sonographer (the person who performs the test) checks the overall growth of the baby’s organs and the formation of the body structure to ensure that the growth is normal. Let us understand more about anomaly scan and also answer FAQs in detail.

What is an Anomaly Scan (Ultrasound level 2)?

An anomaly scan, also known as the ultrasound level II, is a mid-pregnancy scan that takes a closer look at your baby and the uterus (womb). In this scan, the sonographer can see whether the baby is developing normally and will also check the position of your placenta, the umbilical cord, and amniotic fluid around the baby. This scan is also known as morphology scan or 20-week scan. It is important to note that the purpose of this scan is to check your baby’s health and not to determine the gender of the baby.




Why Should you go for an Anomaly Scan?

As mentioned above, an anomaly scan is performed to determine the growth and health of your child. It is not mandatory to get this scan done, but it is highly recommended to monitor your child’s growth. Getting an anomaly scan procedure done is also an opportunity for the parents to see their child in the womb and have some beautiful memories to carry home.

When is an Anomaly Scan done?

An anomaly screening is done in the second trimester of pregnancy. This is when you are around 20 weeks into pregnancy. It can be done anytime between 18th and 23rd week of pregnancy. This 18 – 23 weeks pregnant ultrasound test helps ensure that the child’s growth is normal and all critical organs are developing correctly.





How to Prepare for an Anomaly Scan?

A pregnant researching the internet
Getting an anomaly test during pregnancy is a normal process, and this does not require any special preparation. Here are a few tips that can make the scan quick, comfortable and efficient:

  • It is advised to relax before the scan. Reach the diagnostic centre early and get comfortable.
  • For this scan, it is best to have a full bladder when you come for the test, as the scan cannot be performed on an empty bladder. You might have to wait a bit longer if your bladder is not full enough.
  • Like most other routine pregnancy scans, even anomaly scan requires you to expose the tummy from belly button to the pubic bone and hence it is advised to wear clothing which can be easily adjusted. Also, high heels will have to be removed before the test, so it is best to avoid such footwear.
  • You might be required to remove any jewellery that is on your body during the scan.
  • Carry all your previous tests reports and medical records so that they are readily available if needed.

How is an Anomaly Scan Done?

The anomaly scan or the ultrasound scan uses sound waves to produce images inside the body. The sonographer will apply a water-based gel on the part which needs to be scanned and will use a transducer to collect the sound waves that bounce back. These waves will be used by the computer to create an image of your child. Usually, there is no radiation exposure in this process as the examination does not use ionising radiation. The scan does not hurt.
The anomaly scan takes about 20 minutes to complete, and the sonographer will usually allow you to have a look at the scan and point out to different parts of the child’s body as well as the heart-beat. The sonographer will not disclose the gender of your baby as India’s laws on pre-natal diagnostic techniques prohibit hospitals from doing so.




What can this Scan Detect?

The primary purpose of the scan is to ensure that the baby is growing well without abnormalities. The anomaly sonographer looks for the following things during the scan:

  • The sonographer will check if the baby’s heart is developing and functioning correctly. All the arteries and veins which carry blood to and fro from the heart shall be examined.
  • The baby’s face is checked for cleft lip. However, spotting a cleft lip is difficult and might not always be picked up during the scan.
  • The sonographer checks if your foetus has two kidneys and whether the bladder is getting filled or not. In case the bladder is empty at the beginning of the test, it should be easy to observe it getting filled during the scan.
  • The shape of your baby’s head is also checked, and brain problems, if any, are identified.
  • The sonographer also checks whether the baby’s spine is developing properly and whether the skin on the back covers it up properly.
  • The sonographer will also check your baby’s arms, legs, feet and hands to ensure that they are growing properly.
  • The abdominal wall will be checked to ensure that it covers all the organs in the front. The sonographer will also have a look at the baby’s stomach.
  • The sonographer will check whether there is sufficient amniotic fluid around the baby to provide protection
  • The position of the placenta is also checked during the scan. In case the placenta is placed low in your uterus, your doctor will inform you of the same. This situation is known as placenta praevia, and another ultrasound is recommended in the third trimester to see whether the placenta has moved away from the cervix. A low lying placenta even in the third trimester might cause excessive bleeding during delivery, but a low lying placenta during 18-20 weeks of pregnancy is not a cause for concern.
  • The sonographer will also measure your baby’s body parts during the scan and compare this with the standard growth during that stage of pregnancy.

The sonographer will usually take anomaly scan measurements of the following:





  • Head circumference
  • Abdominal circumference
  • Thigh bone

What does an Anomaly Scan Reveal about the Baby?

Images of 3D ultrasound anomaly scan on a female foetus four months into the pregnancy

  • The scan will show a black and white image of your baby. The scan performed is usually a 2D scan, and you can see only one side of your baby, but if you go for a 3D or a 4D scan, you can see a right image of your baby’s body and from different angles.
  • The scan will show a general situation of your child’s body. The sonographer will look into the growth of the baby and identify abnormalities (if any). The scan will help you determine if you have one or more babies and the sonographer will also take measurements of your baby’s body parts to ensure normal growth.

Can the Anomaly Scan Harm the Mother or the Baby?

Unlike X-rays, the ultrasound anomaly scan does not use ionizing radiation and hence is not harmful to the mother or the baby. Also, the sonographer takes precautions to ensure that the mother is comfortable during the scan.
The application of gel and usage of the transducer could make the scanning process a little uncomfortable, but it is not harmful or painful to get the scan done.

What is the Purpose of an Anomaly Scan?

The principal purpose of anomaly scan is to allow the sonographer to monitor the growth of the baby and determine the health of vital organs of the body and the structure of different body parts. The scan is used to identify and assess any significant abnormalities that the child may have in any of the body parts. Getting a mid-pregnancy ultrasound scan is recommended to monitor the well-being of the child.
The focus is usually on organs such as the brain, heart, kidneys, spinal cord and placenta placement in the womb.




What do the Anomaly Scan Results mean?

Anomaly scan results indicate the progress of the child in the womb and help in determining the growth graph of the child. The results will either show that the child is developing normally and as per the usual pace or it will throw up abnormalities if any. In case of defects, your doctor will discuss the corrective action that can be taken to solve any deviations of the child from regular growth graph.

Which Abnormalities are Detected in an Anomaly Scan?

There is a list of observations that the sonographer makes while doing the scan and covers the baby from tip to toe. The foetal abnormalities detected might be normal ones that can be treated after your child is born. If they are severe, they will require immediate action.
Here are some of the abnormalities that can be detected in anomaly scan:





  • Cleft lip
  • Spina bifida (defect of the spinal cord)
  • Heart problems
  • Kidney problems
  • Anencephaly, or missing the top of the head
  • Problems in the limbs (for example – too short limbs)
    While the scan is done with the purpose of finding abnormalities, it is not easy to spot one in the baby. For example, if there is a problem with the abdominal wall, kidneys, limbs or spinal cord, there are good chances that the scan will detect them. But the likelihood of spotting defects in the heart, assessing if there is a hole in the muscle which separates the chest and abdomen, or detecting excess fluid build-up in the brain is comparatively less.
    In case an abnormality is spotted, the sonographer might refer the report to another person to confirm the observation made and then discuss the plan of action to be followed.

Is an Anomaly Scan Accurate?

A mid-pregnancy ultrasound scan is very important as it will help determine the growth of the child and aid in early detection of abnormalities that the child might be developing. The anomaly scans are usually accurate and present a clear picture. However, it is not always necessary that scan is 100% accurate and shows correct results at all times.
This is because it is difficult to determine abnormalities in the baby, especially in the vital organs, and an anomaly scan may or may not show up the same. A sonographer may also need to scan the abdomen multiple times to get a clear picture of the baby. Usually, the parents are also asked to give consent of their understanding that results of the scan being performed might not be 100% accurate.

What if the Scan indicates a Problem?

Once again, it is essential to understand that an anomaly scan report is not always 100% accurate and the observations might not always be correct. Also, note that the chances of identifying a severe problem at this stage are rare. However, in case a problem is spotted, you will be given advice on how to deal with it and the steps you must take. In case any problem is identified, you can expect the following next steps:




  • There might be situations where the sonographer has not been able to see everything since your baby was not in a good position while the scan was being performed. Also, the scan might not be consistent if you are overweight as body fat can interfere with the sonography. In such situations, you might have to get the scan redone at the 23rd week
    In case the sonographer finds or thinks that there is a problem, you will be informed immediately and it is recommended that you see a foetal medicine specialist within 72 hours of the scan result.
  • You might be asked to get a foetal echo scan done in case there is a suspicion of your baby having a heart problem. This scan will take a detailed look at your baby’s heart
    Your doctor will recommend the suitable solution for the detected problem. This will depend on the severity of the problem and whether or not it requires intervention at this stage. The solution usually involves surgery to the child after birth. In case of severe problems, certain surgeries might also be performed while the child is in the womb.

Seeing your baby taking shape inside your womb is a unique experience for parents. In most cases, you are allowed to take your partner along with you to witness this moment. The diagnostic centres performing these scans usually offer pictures and video copies of the scan for you to carry back as memories.
Getting an anomaly scan is always advised as it plays a very important role in ensuring that the child’s growth is normal.

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