Fetal Development in 17 Weeks Pregnant

By this week, you are almost in the midst of the second trimester. At 17 weeks you are starting to show and gaining weight.

There is a gradual fetal development in 17 weeks pregnant and the baby is growing rapidly.

Between 17th and 20th week of your pregnancy, lungs of the baby are getting closer to be able to function, whereas the brown fat layers start to develop.

Fetal Development in 17 Weeks Pregnant

Here is the fetal development during this week.

Fat layers

In this week, the baby begins to plump up a little bit. The fat that has been obtained is also known as adipose tissue. It helps in producing and retaining the body heat. Fat tissue is essential for metabolism too, as it serves as a source of energy. In the later stages of the pregnancy, the baby will develop extra fat layers.

Baby size

In this week, your baby weighs about 5 ounces; and when measured from crown to rump, your baby is about 13 cm long.


Your baby has been working out on 2 basic kinds of reflexes for some weeks, that is swallowing and sucking. After the baby’s birth, he/she will be having almost all the reflexes that you have, which help the baby to survive and also to learn about this world.

Baby’s gender

If your baby is a girl baby, special tissues are developing into the vagina and uterus. If your baby is a boy baby, the same tissues are developing in another path, penis has developed and his prostate has started to take shape. The testosterone producing cells, which were developed a month before, are important in managing these developments.


The eyes of your baby are now looking forward, but still they are firmly closed. The retina of the baby has become sensitive to the light.


Meconium which includes the products of swallowed amniotic fluid, cell loss, and digestive secretion is gathering in the bowel.

Other developments

  • The skeleton is converting from the cartilage form to the bone. The bones stay flexible to easily pass through the birth canal.
  • You can also feel that your uterus is just below the belly button.
  • Little hiccups will continue and you may feel them.
  • In your baby’s lungs, the air passages finish branching. By this week, the lungs prepare to absorb oxygen.
  • The baby’s skeleton is in the form of rubbery cartilage, which will become harden later. A protective substance which is known as myelin begins slowly to cover around the spinal cord.


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