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Pregnancy health centre

6 weeks pregnant

WebMD Medical Reference
Medically Reviewed by Dr Rob Hicks


How is your baby growing at 6 weeks?

If you saw an ultrasound of your developing baby no one would blame you for thinking it looks a bit like a tadpole. Its body will be curving into a "C" shape and the neural tube along the back will be closing up. There will be a bump at the end of the neural tube that will become the brain and head – in fact the brain and spinal cord will soon comprise the largest, most compact tissue of the embryo. The heart will be obvious as a large bulge.

At 6 weeks, the size of the embryo is 5 – 8mm – about the size of a lentil – from its head to its bottom. Known as the "crown–rump length", this is the preferred measurement method because the developing embryo will have a tail and be curved, and when legs form later on they are usually curled up, making it difficult to get an accurate measurement from head to toe.

An ultrasound can sometimes pick up a primitive beating heart at this stage. Although the heart is beating and pushing fluids through the body at only 23–25 days after ovulation, the embryo will not have developed a circulatory system with blood vessels.

New features will be appearing in the embryo. Thickened circles will form on both sides of the head – these will later develop into the eyes – and the passageways of the inner ears will begin to develop. The liver cells are now beginning to form before the rest of the digestive system, and small "limb buds" will appear where the baby's arms and legs will grow. The first thin layer of transparent skin appears covering the embryo.

How are you changing in week 6?

You should begin to feel pregnant if you have any of the common early signs of pregnancy. Your breasts may be tender and ache, you may experience the nausea and vomiting of morning sickness – and not just during the morning – and hormonal changes may also be making you urinate more often. Don't be surprised if fatigue seems to be an issue this week – your body needs to adjust to the demands of pregnancy. With fluctuations in hormones, you may also be feeling moody.

What you need to know in week 6

With the rapid developments of the neural tube in the last several days – which is the beginnings of the central nervous system – taking folic acid to prevent spinal cord defects has been crucial. Continue to take this supplement until 12 weeks pregnant, and a daily vitamin D supplement throughout pregnancy, and follow good antenatal habits. If you haven't stopped smoking already, do so, and avoid all alcohol.

Next: 7 weeks pregnant

Additional pregnancy week by week pages:
8 weeks pregnant   |  9 weeks pregnant    
10 weeks pregnant
 11 weeks pregnant

Reviewed on November 20, 2017

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