13 Week Ultrasound

Your baby isn’t just getting bigger, but also moves in a manner that wasn’t able earlier. All the principal organs and body parts are in the right places, and it is visible on the ultrasound. Finally, you can find out the gender of your baby. The unpleasantness of the first trimester is slowly disappearing and the risk of miscarriage is lower. Regardless, you still need regular supervision by your doctor.

How Will Your 13-Week Ultrasound Be Done?

An ultrasound scan typically takes approximately 10 minutes. There are two methods of the examination, the trans-abdominal and the trans-vaginal. The procedure is painless, regardless of whether it is a trans-abdominal or trans-vaginal examination.

3-D ultrasound is interesting to the parents since they can see their baby in 3D with all of the body parts. It can provide 3-dimensional images made of a series of images, thin slices of the baby, and the computer processes these images and presents them as a 3-dimensional image.

The difference between an ordinary ultrasound and 3D/4D is only in the image quality, but the procedure is the same.

Baby’s Development at 13 Weeks

Digestive Tract

The intestines of your baby are continuing settling in their permanent place in your baby’s abdomen. At the same time, the pancreas starts producing insulin and the liver starts with bile secretion. The vocal cords start with development as well. Any waste of your baby’s body is converted to urine in the kidneys. The urine gets excreted to the amniotic fluid surrounding the baby via kidneys.

Genital Organs

The testes or ovaries are already distinctive depending on the sex of your baby. The female fetus will have its eggs formed in the ovaries counting 2 million at this stage but will go down to a million at the time of the birth.

Extremities and Muscles

Your baby can put his tips of the fingers together and suck while sucking muscles in the cheeks are developed, as well. Bony tissues start to grow in baby’s tiny arms and legs. The reflexes, that the baby will need, later on, started with its action. Therefore, his muscle control is better than last week. The fingerprints at your baby’s fingertips begin to outline in its unique manner.

As the pregnancy continues, the amniotic fluid is increasing in volume and your baby has lots of room to move inside the uterus. This week, you may have up to 25 ml of amniotic fluid.

What Can You See About Baby’s Changing?

2First of all, your baby grows fast. He/she is now 7.5 cm (2.9 inches) long and weighs around 23 g (0.81 oz) and looks more and more like a little human with the proportional head and body. If you have 3D/4D ultrasound examination, you can see that the baby’s skin is still transparent since there is still no underlying body fat, so it is possible to see the growing veins, blood vessels, and internal organs.

You can see the movements of your baby’s heart and also you can hear the heart beating. It is currently twice as fast as your own, but it will slow down to a normal rate before the birth occurs.



1The best part of the examination is when you see that your baby already learned to kick their legs, turning their head even swallowing, yawning and putting his/her thumb into the mouth! You can see also, that your baby’s toes are now separate, and they’re about the same length.

Your sonographer can show you developing of the baby’s clavicle/collarbone and femur/thigh bone. He can also show you hemispheres of your baby’s brain. The other exciting fact about your baby is his/her gender. Now it is possible to tell if it’s a boy or a girl. The male fetuses showed as dome-shaped genital swelling, and the females as three or four parallel lines representing the labia.

girlAn image of a girl.

boy An image of a boy.

The visibility gets better with older gestational age, it doesn’t depend on sonographer’s ability. But, as you can see, visibility is also better on 3D ultrasound images.  Whichever scan we use to determine the gender of the baby, with the ultrasound at the 13th week of pregnancy, it can be difficult to differ.

What Complications Can Be Diagnosed?

Your baby has all the principal organs and body parts by now, as you can see. He grows and changes so fast. The risk of miscarriage is lower at the end of the first trimester. In the first 12th week of pregnancy, 80% of all miscarriages occur, so the beginning of the pregnancy is the riskiest. Regardless, it is useful to check the fetal growth at this week, as well as the warning signs of possible complications. Therefore, some women are still at risk. One of the cases is the incompetent cervix. It means that the cervix is open more than 2.5 cm during the pregnancy, or when the cervical length is less than 20 mm. Its tissue is weak and can cause or contribute to premature birth. Your doctor may diagnose it by an ultrasound or by manual examination.



The treatment for incompetent cervix is the cervical suture.  During the treatment, a surgeon will put the stitches around your cervix, to keep it closed. It will help you to save your pregnancy and prevent miscarriage.

Possible Symptoms of Miscarriage:

  • Cramps in the stomach followed by heavy breathing
  • Sharp pain in the abdomen, pelvic region or the lower back
  • Heavy bleeding
  • Blood clots passing through vagina
  • Fetus movements which are felt during the fourth month of pregnancy. It the baby stopped moving, it can be a bad sign.

If you have any of these signs, contact your doctor for urgent medical intervention.

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