Anomaly Scan During Pregnancy

Anomaly Scan in Pregnancy

Medically Reviewed By
Dr. Sanjana Sainani (Gynecologist/Obstetrician)
View more Gynecologist/Obstetrician Our Panel of Experts

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 pregnancy term to ensure that the baby’s growth is normal and on track. An anomaly scan is one such scan that 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’s understand more about anomaly scan in detail.

What Is an Anomaly Scan (Level 2 Ultrasound)?

An anomaly scan, also known as the level 2 ultrasound, 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.

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, including his structural normalcy. It is also done to raise suspicion of any abnormality which might require further testing. It involves a head to toe study of the baby including the heart, the liver, the kidneys and the brain. In other words, it is mandatory to get this scan done to monitor your child’s growth by gauging the development of his organs. An anomaly scan is also an opportunity for the parents to have some beautiful memories to carry home in the form of images/pictures of the foetus.

When Is an Anomaly Scan Done?

An anomaly screening is done in the second trimester of pregnancy; usually between 18 to 20 weeks into the pregnancy. The ultrasound scan 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 scan during pregnancy is a normal process, and this does not require any special preparation. However, some tips like those given below can make the scan quick, comfortable and efficient:

  • It is advisable 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 may reach early and drink enough water before you the scan.
  • Like most other routine pregnancy scans, even anomaly scan requires you to expose the tummy from the belly button to the pubic bone, and hence it is advised to wear clothing which can be easily adjusted.
  • 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 is done using sound waves to produce images inside the body. The sonographer will apply a water-based gel on the belly and 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.

The scan does not hurt, but the sonographer may apply slight pressure to get the images. It takes about 30 minutes to complete the scan, after which you are allowed to have a look at the images. The sonographer can help you identify different parts of the child’s body and, sometimes, also show his beating heart. The gender of the baby is never revealed though, as there are stringent laws on pre-natal diagnostic techniques in India and hospitals are prohibited from doing so.

What Can an Anomaly Scan Detect?

The primary purpose of the scan is to ensure that the baby is growing well without abnormalities. The anomaly sonographer checks the following parts of the baby’s developing body during the scan:

  • The Baby’s Heart – The sonographer will check if the baby’s heart is developing and functioning correctly. All the arteries and veins that carry blood to and from the heart are also examined.
  • Cleft lip – 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 Foetus’ Kidneys – 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.
  • Development of the Head – The shape of the foetus’ head is also checked. Problems related to the development of the brain, if any, are highlighted immediately.
  • Development of the Spine – The sonographer also checks if the baby’s spine is developing properly and whether the skin on the back covers it up properly.
  • Limb Development -The sonographer will also check if the baby’s limbs are developing appropriately.
  • The Abdominal Wall – 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 and highlight any abnormalities related to the stomach from its appearance.
  • Amniotic Fluid- The sonographer will check whether there is sufficient amniotic fluid around the baby to provide protection.
  • Placenta – The position of the placenta is checked during the scan. In case the placenta is placed low in your uterus, your doctor will inform you the same and prescribe another ultrasound during the third trimester to see whether the placenta has moved away from the cervix. In medical terms, this scenario is called placenta praevia. A low lying placenta in the third trimester might cause excessive bleeding during delivery, but a low lying placenta between 18 and 20 weeks of pregnancy is not a cause for concern.
  • Measurements of the Foetus – 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:
  • Circumference of the head.
  • Circumference of the abdomen
  • Measurements of the 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 more accurate image of your baby from different angles. As mentioned earlier, the scan will show a general situation of your child’s body, which includes his growth, development and presence of abnormalities (if any). The scan also helps confirm if you have one or more babies.

Can an 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 the anomaly scan is to allow the sonographer to monitor the growth of the baby and determine the health of his vital organs. 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 the organs such as the brain, heart, kidneys, and spinal cord of the foetus, the would-be mother’s uterus, the placement of the placenta placement, etc.

What Do the Anomaly Scan Results Mean?

Anomaly scan results indicate the development of the child in the womb and help in determining the growth graph of the foetus. The results will either show that the foetus is developing normally or it will show up abnormalities if there are any. In case of defects, your doctor will discuss corrective actions.

Which Abnormalities Are Detected in an Anomaly Scan?

There is a list of observations that the sonographer makes while doing the scan. The list also includes foetal abnormalities, some of which can be treated after your child is born, while some, if severe, can be given immediate medical attention.

Here are some of the abnormalities that can be detected in anomaly scans:

  • 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, limbs that are too short

While the scan is done with the purpose of finding abnormalities, it is not always 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.

Is an Anomaly Scan Accurate?

A mid-pregnancy ultrasound scan is very important as it can help determine the growth of the foetus and aid in early detection of abnormalities that the foetus might be developing. The anomaly scans do give images; however, it is not always necessary that the scans are 100% accurate and show 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 the 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 advised how to deal with it. The following points should prepare you to deal with such a situation.

  • There might be times when the sonographer has not been able to see everything since your baby’s position was such that the ultrasound couldn’t pick up any waves form the images. 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 during the 23rd week of pregnancy.
    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 the observations indicate that your baby could have a heart problem. Your doctor will then recommend a 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. In some cases, the child has to undergo surgery after his birth, while in some, surgeries might be performed while the child is in the womb.

Seeing the baby developing inside the 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 collect as memories too. Nonetheless, getting an anomaly scan is always advised as it plays a very important role in ensuring that the child’s growth is normal.


Also Read:

Transvaginal Ultrasound Scan

3D & 4D Pregnancy Scans

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