18 Week Pregnant Ultrasound


As you enter your 18th week of pregnancy, your doctor may recommend you a detailed ultrasound examination to assess the growth and development of your unborn baby. Where for some women this may be the first look of their unborn baby, others may already have had an ultrasound scan earlier than this. Here in the following article, we shall discuss all that you need to know about 18-week pregnancy ultrasound.


Why Should You Have Ultrasound Scan at 18 Week of Pregnancy?

Ultrasound scan in your 18-20 week of pregnancy is a part of your routine check-up. Your doctor may advise you an ultrasound scan because of following reasons:

  • To establish the foetal age.
  • To check the number of foetuses (one or more than one)
  • To make estimates about the date of delivery.
  • To check the quantity of fluid around the foetus.
  • To check the cervix and the birth canal.
  • To see the position of the placenta

What Preparations Are Needed to Done This Scan?

There is not much preparation required for the scan. Drink sufficient water to keep your bladder full. This keeps your uterus in the correct place for the scan and helps your doctor to see the foetus clearly. Refrain from drinking too much water as it can make you extremely uncomfortable during the scanning process. You may ask your radiologist in advance as to how much water you are required to drink.

It will be a good idea to wear comfortable and loose clothes for the process so that the radiologist has easy access to your abdominal region.

How Long Does Eighteen Week Ultrasound Take to Complete?

On an average, an ultrasound scan around 18-20 weeks of pregnancy may take from 30 to 45 minutes.

How Is This Scan Performed?

The radiologist will apply a gel on your abdominal region and run over a transducer over your belly. The scan is carried out in real time, which means what you will see on the screen, will be happening inside your womb during that time. You may ask the doctor to explain the images that are flashed on the screen. The main purpose of an ultrasound scan is to assess the foetal health and well-being.

What Can You See on 18 Week Scan?

You may ask your radiologist in advance if you wish you view the images of the scan on the screen. Though most hospitals or health centres provide for this facility, it is always good to inform in advance.

  • If you have an ultrasound scan for the first time, your doctor will tell you how many babies you are carrying and also your expected date of delivery.
  • You will also hear the foetal heartbeat for the first time.
  • Your radiologist may also show you your baby’s face, arms and legs. However, you may find it difficult to spot your baby’s organs, but that is absolutely fine because it is a bit difficult to understand the scan. You may ask the radiologist to help you understand the scan better.
  • The bones of the baby at 18 weeks pregnant ultrasound will appear white on the screen, the amniotic fluid will appear black, and the soft tissues will appear grey in colour.

After showing you the glimpses of the scan, the radiologist will then turn the screen towards himself and make other assessments. You will be handed a soft copy or a DVD of the scan after the process is over.

Are There Any Risks or after Effects of Ultrasound at 18 Weeks? 

There are no after effects of an ultrasound scan, and you can easily resume your day to day activities. At the same time, there are no scientific pieces of evidence available that prove any ill-effects of an ultrasound scan on the expectant mother and her unborn child. There are no harmful radiations used to obtain the images instead very high-frequency sound waves are used for the purpose. In some cases where the foetus is farther away from the transducer, the process becomes little difficult and may take a bit longer. You may even be called after a few days for a re-scan. In case of twins and multiple pregnancies also your doctor may face difficulties in establishing the foetal structures and you may be asked to come again after a few days.

Which Abnormalities Can Be Seen on The 18th Week Ultrasound Scan?

Some of these abnormalities may include the following:

  • Short limbs or absence of limbs
  • Cleft lip
  • Abdominal wall defects (protruding intestines)
  • Abdominal wall defects (protruding liver)
  • Abnormality related to the absence of top of the head
  • Severe kidney problem
  • Problems in the spinal cord
  • Excessive brain fluids
  • Chromosomal abnormalities
  • Severe heart defects
  • Any kinds of holes in the muscles separating abdomen and the chest.

These medical conditions are not very common and rarely occur in babies. However, it is a good idea to get an ultrasound scan and rule out the possibilities of all these medical conditions.

What if There Are Signs of Problems on the Scan? 

In case the radiologist is not able to see the foetus clearly in the scan, you will be called at a later date for a re-scan. In case you are obese, or the baby is tucked too deep into the womb, a re-scan may be suggested too. However, if your doctor sees any kind of above-mentioned abnormality or other defects, you will be told about them. You will also be told to get an appointment with a foetal medicine expert to know about the intricacy of the defect and the options available to you.


In case of serious abnormalities, you may be suggested to terminate the pregnancy. However, some abnormalities may require immediate medical attention soon after birth.

An ultrasound scan at 18 weeks is a great way of knowing about your unborn baby’s health and well-being. Where some parents are too eager for the scan, others may decide not to go for the scan. It is absolutely left up to the parent’s discretion, whether or not they want an ultrasound scan. You may talk to your doctor about your options.