Home Pregnancy Week by Week 20 Week Ultrasound: Why is it Important?

20 Week Ultrasound: Why is it Important?


At 20 weeks pregnant, you are said to have reached the “halfway point” of this journey. You are 4 months and 2 weeks pregnant. By now the foetus has grown to be almost the size of a banana, weighing about 10.2 ounces and measuring approximately 6.5 inches starting from its crown up to its rump.

You have, by now, gained quite some weight, and your belly measures from about 18 to 22 centimetres. You are likely to feel pretty excited at this stage as you know that you’ve successfully come halfway through the path! At week 20, you will also have some vital tests in the ultrasound room, as this is your first major mid-term test.

Everything You Need to Know about Week 20 Ultrasound

week 20 ultrasound

Reasons for an ultrasound during week 20 of pregnancy

An ultrasound at week 20 is required to make sure that your health condition, along with the baby’s, is under control. The main reasons for undergoing the ultrasound this week are:

  • To determine the position of the foetus
  • To check the spine of the foetus
  • To detect the weight and size
  • To examine the overall development of the baby in terms of its internal organs, limbs, brain, and skull
  • To determine the amount of amniotic fluid present inside your body
  • To check the position of the placenta and cord

What to expect during your 20 weeks ultrasound

At 20 weeks, you are definitely excited to see what is going on inside your womb, and how the little one is growing! The ultrasound scan is done to provide you with all these answers. There is an “Anomaly scan” during this week, which is also called a mid-pregnancy scan. Starting from this week, at every visit, the doctor will measure the fundal height, which is the distance between the top of your uterus to your pubic bone.

20 Week Pregnancy: 3D Ultrasound:

The sonographer, in the 3D scan, will check the location of the placenta to detect the position of the baby and its rate of development. You can see the baby actively moving inside the womb, in the pool of amniotic fluid. The baby is also blinking and twitching in response to the external sounds! This also determines another factor, which the OB might as well tell you, which is that the baby’s hearing sensations as well as the brain cells are developing well. Thus, it can respond promptly, based on its reflexes.


You will also be able to view that the size of your baby has considerably increased from what you had seen last time. Indeed, the little one is growing too quickly! You will also be able to see that the hands and feet of the baby have almost developed by now, as they are not webbed like they were previously.  The baby’s bones will be visible clearly, like small white pearls, and the fluid in the amniotic sac will be seen as black. Many mothers freak out on seeing that the tissues of their babies are dark grey and freckled. Your gynaecologist will explain that there is nothing to worry about, as this is a normal phenomena. Through time, the colour will change and the texture will become smoother.

20 Week Pregnancy: 4D Ultrasound:

In the 4D screen of the ultrasound test, the gynaecologist can clearly view the baby’s genitals and other pelvic details that will allow them to determine its sex. You can also get a clearer view of the baby’s distinctive facial features like the eyes, nose, and lips. If you look closely, you can also see the internal chambers of its heart and the parts of its brain! Now, you would probably like to grab a tissue!

Sometimes, there may be another monitor located near the foot of the couch in which you are lying, so that you can view the compete anatomy of the baby, along with its intricate details like the kidneys, veins, and pelvic region.

During the ultrasound session, the gynaecologist will recommend some genetic tests to be done in order to ensure proper development of the foetus. There will be some hormonal tests and a blood test in which the gynaecologist will try to detect inborn defects in the foetus, gestational diabetes, brain cell issues, and carcinogenic content in your body. Based on the situation, the doctor might also ask for a urine test to detect the pregnancy hormone levels, which might have an effect on the foetus. If all the results turn out to be A-OK, you are not in potential danger!

During the 20th week ultrasound, you can ask the sonographer for cuttings of the printed images and DVD recordings of the baby’s movements and actions!

20 Week Ultrasound: Twin Pregnancy

Apart from all these, if you are pregnant with twins, the gynaecologist and the sonographer will make it a point to check the sizes of the babies’ skulls and brains. It is important to ensure that both the babies are growing approximately evenly and absorbing equal quantities of nutrients from the mother. Neither of them should face growth problems due to being at the behest of the other. If there are some discrepancies in this report, the doctor will provide you with some supplements or even ask you to go through some other vital tests, until such time that everybody is out of danger.


After all your tests are done, and you are deemed out of danger, all you need to do is follow your diet chart and relax! You’ve come all the way till here, yet you have another half of the journey left. Sit back, follow the regulations, relax, and enjoy!

Hope this article was of help for all our parents!! Please share your comments/queries/tips with us and help us create a world full of Happy and Healthy Babies!!