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Week by Week Pregnancy Ultrasounds

by Tasha Mayberry


No matter how much your pregnancy symptoms try to put you off, the feeling that a new life is growing inside you will give you all the enthusiasm and joy in the world. It is natural for your excitement to multifold whenever your ultrasound dates approach because those are the times when you get to see your little one and their development. But, no matter how prepared you are, when the time arrives, you wouldn’t know what to expect at your ultrasounds. So, here is a brief overview of your week by week pregnancy ultrasounds:

Weeks 1 & 2

During your first two weeks of pregnancy, there will be no ultrasound image of your baby, because technically you are not pregnant yet. However, these weeks will be used by your doctor to estimate your delivery date, because your due date will be calculated using the date of the first day of your last menstrual cycle.

Week 3

This is the week when your pregnancy actually begins, because this is when fertilization happens, meaning, the sperm joins with your egg as it gets to the uterus. Once they join and fertilize, the cells start dividing, slowly starting the development of your little being, which your sonographer will be able to capture during an ultrasound in the following weeks.

Week 4

By now, you would have had a positive pregnancy test, and during your ultrasound this week, you will be able to see a small circle at the center. Though you may not find much right now, this circle is what is called the gestational sac, which acts like an encasement for your baby.

Week 5

Though it might be hard to believe, the fetus in your womb will now be the size of a pen dot (yes, that tiny!). Your embryo is starting to take shape, where one end will become your little one’s head and the other his/her bottom.

Week 6

In this week’s ultrasound, you could see a major change in your developing embryo, where your baby takes a C shape, curving inwards, and with the umbilical cord in the middle. You could also find small sprouts where the arms and legs will develop pretty soon. Above all, this week, you could hear your baby’s heartbeat for the first time, something you will never forget for the rest of your life.

Week 7

At week 7 of your ultrasound, your growing baby will be the size of a blueberry. He/she is now developing in the amniotic cavity, and the amniotic fluid in this cavity gives your little one room to develop and move.

Week 8

During this week, your baby’s head is getting bigger to accommodate the growing brain, and their arms, legs, and whole body are getting longer. But, he/she is still in the curved C-shape.

Week 9

As you start your third month of pregnancy, your baby continues to grow rapidly, and even though you don’t feel them yet, your little one is starting to make movements. In an ultrasound during this week, the sonographer would be able to measure the length of the baby, which would be slightly over an inch.

Week 10

As you hit your tenth week, your baby is growing really fast, and he/she is now officially a fetus and not an embryo. During an ultrasound at this stage, you could notice that your baby looks more like a newborn, with their arms and legs visible, and an overall recognizable structure.

Week 11

At week 11, your baby’s facial features get more defined, and their neck is growing as well. You could see their developing facial bones as bright white areas on the ultrasound, and their head still holds more than 50% of their overall body size.

Week 12

During this week, your little one is over 2 inches long, and his/her facial features are becoming more and more like what you would see in a newborn. Oh, and your baby could be sucking their thumb!

Week 13

The fetus is almost 3 inches long from crown to rump. During this week, their urinary tract system and kidney will start functioning, which means he/she will start peeing. Their arms and legs are becoming more proportionate to their overall body size.

Week 14

You are now one step closer to finding your baby’s gender because their genitalia is now formed. He/she now weighs around 2 ounces and about four inches in length.

Week 15

Your baby is now about the size of a grapefruit, and his/her skull bones are now forming and hardening. If you take an ultrasound this week, you could see your baby smile and make other funny faces, and you cannot help but laugh yourself.

Week 16

When you are 16 weeks pregnant, you could just start feeling your baby move, although this timeframe is usually different from one pregnant woman to another. Your baby is growing fast now and his/her lower limbs are well-developed. Their facial muscles are also beginning to work. In this week’s ultrasound, you will be able to recognize his/her facial feature more profoundly.

Week 17

Your is now more than 4 ½ inches in length and weighs around 3 ½ ounces. In your ultrasound, you could see your baby’s tiny hands and legs close-up and possibly look at him/her touching their face.

Week 18

You are almost halfway through your pregnancy, and during this time (between 18 and 20 weeks), your doctor will need you to take an ultrasound to evaluate the anatomy and growth of your baby. If your baby is in the right position, your sonographer would be able to determine your baby’s gender.

Week 19

Your baby is around 6 inches long and weighs 7 ounces. His/her arms and legs are constantly developing, and you will start to feel their movements (if you haven’t already!) in the next couple of weeks. In the ultrasound images, you will be able to see the baby’s bone clearly, since their skin is still translucent.

Week 20

You have successfully reached the halfway mark of your pregnancy, and ultrasound during this week will reveal your little one’s anatomy more clearly, and the development of their different body parts and organs.

Week 21

Your baby is now big enough for you to feel their movements. In this week’s ultrasound, you could see your baby moving a lot, wiggling his/her hands and legs frequently. Your sonographer will be able to identify the baby’s heart and lung tissue.

Week 22

Your baby will now measure over 7 inches in length and weigh over 12 ounces. His/her eyebrows are starting to form, and so is their hair. Your baby will now be able to hear you more clearly, thanks to the development of their inner ear bones, which means you should talk to them through your tummy more often.

Week 23

At week 23, your baby is gaining weight rapidly, which is going to be significant in the coming weeks. As he/she is over 8 inches long, imaging their entire body during an ultrasound will now be difficult.

Week 24

Your baby is getting stronger and stronger, and he/she can now recognize your voice. During an ultrasound, you could see your little one trying to grab everything around them, and also their pedaling motion. You might also notice them play with the umbilical cord.

Week 25

Your baby’s senses are starting to function now; their ears are in their final position and they can hear a lot more clearly and recognize your voice. You may notice your baby responding to some loud noises. By now, he/she might also have their regular sleeping time.

Week 26

Weighing close to 2 pounds, you will notice your baby’s kicks getting stronger week after week. At this stage, even your partner should be able to feel his/her movements easily. In an ultrasound, you could see your baby’s hair, eyebrows, nose, mouth, and other features more clearly and watch them move as well.

Week 27

Since your baby is growing, he/she will now be big enough to not fit in the ultrasound frame anymore. Again, this week’s ultrasound will give you a clear picture of your little angel’s features, and their growth now will be more internal than external.

Week 28

Welcome to your third and final trimester! Your baby’s hair is continuing to grow, and you might even see it waving in the amniotic fluid. He/she can now open and close their eyes, and they might start to point their head down anytime now, to prepare for birth.

Week 29

Your baby’s muscles are becoming stronger and bones harder, which you might notice from his/her kicks getting stronger each passing week. With their hearing well-developed, you might notice them getting startled by loud noises, and you might also watch him/her turning their head towards you during an ultrasound.

Week 30

At week 30, your baby is gaining weight rapidly, at a rate of about ½ pound per week, and this will make it more difficult for them to move around in your womb. As a result, you might feel their kicks or movements to be less frequent. In a 3D scan at this stage, you could notice how well your little one’s features have developed.

Week 31

Weighing over 3 ½ pounds now, your baby has a lot to show you in the ultrasound, if you have one scheduled around this time. You could see some of their movements captured, take a closer look at his/her face and other features, etc., and the images can be more distinct on a 3D image.

Week 32

During this time, as your baby continues to put on weight and their organs develop, your doctor might want an ultrasound for different reasons, including fetal growth evaluation, to determine fetal presentation, to evaluate baby movements, etc.

Week 33

Your baby is now about 12 inches long, crown to rump, weighing around 4 ½ pounds. He/she is getting chubbier each day, and ultrasound at this stage will give your doctor a complete look inside your womb as you approach your due date.

Week 34

At 34 weeks, your little one can now hear, see, learn, and also remember. He/she is almost ready to enter this world. Weighing around 5 pounds, his/her movements would be less frequent now, due to lack of space. However, you can still see them move during an ultrasound.

Week 35

An ultrasound during this week will show you the full development of your baby’s features, from their lips to ears, and more. You might even see him/her pouting during your ultrasound. The baby is still learning to breathe, and their internal organs continue to mature.

Week 36

In the next four weeks or less, you will have your little bundle of joy in your arms, and at week 36, you will notice the same in the ultrasound as you did last week, except that your baby would have gained some weight.

Week 37

Congratulations, your baby is now full term! This week, you might be asked to take an ultrasound to measure the amniotic fluid level to know if there is enough to keep your baby moving.

Week 38

Your baby’s room for movements is getting less and less, but he/she will still continue to move, just less frequently. If the movements seem to be too infrequent, you could be asked to take an ultrasound, in which the little one’s heartbeat will be tracked.

Week 39

With the delivery day fast approaching, your baby is more likely to have taken a head-down position, to support normal delivery, which will be determined in an ultrasound.

Week 40

Your little human is fully grown and ready to meet you anytime now. In most cases, you wouldn’t be having an ultrasound this week, but in case you do, you could notice the little one in the breech position, or head-down position, ready to come out to the new world.