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ultrasound of human fetus at 17 weeks and 2 days

Your baby today

Here, the baby's legs are in the typical crossed-legs position. The right arm is on the right side of the image. The limbs and umbilical cord appear to be in a tangle, but the umbilical cord is filled with a jellylike fluid and does not become compressed.

The tiny embryo was once dwarfed by the placenta but now your baby has outgrown it and will continue to do so.

In the early stages of pregnancy, the placenta grew at a far greater rate than your baby. Your baby has now caught up and from now on will be larger than the placenta.

The structure of the placenta will change over the course of the next few weeks as the second wave of cells move into the spiral arteries in the uterus (see You are 14 Weeks and 4 Days). The placenta is currently at its thickest but as it continues to grow, albeit at a slower rate for a time, it thins out.

Your baby's more rapid growth means that at 2.5 oz (70 g) she is now heavier than the placenta and by the time she is full term she will be six or seven times its weight. Nutrients supplied across the placenta provide your baby with energy for growth, but growth is in part regulated by her own insulin production and insulin-like growth factors.

Although your baby has relatively high concentrations of growth hormone, which is responsible for growth after birth, this does not seem to play an important role in her growth during pregnancy.

17 week fetus

The baby is in a typical position, curled with feet and elbows bent. The well-developed ear is still a little low on the side of the head at this point, and the baby's blood vessels show up well.

Focus On... Health

Tackling heartburn

If you're battling with the burning sensation and sour taste of heartburn, try these solutions:

  • Eat smaller meals, and ensure you chew your food well
  • Avoid foods that aggravate your symptoms, such as spicy, rich, and fatty dishes
  • Don't smoke or drink alcohol
  • Drink milk
  • Wear loose-fitting clothing
  • Chew gum after eating, except for mint varieties
  • Remain upright after meals; bending can increase discomfort
  • Don't eat 2 to 3 hours before going to bed
  • Raise the head of your bed by 6 in and lie on your left side.

excerpted from:

Excerpted from Pregnancy Day by Day.
Copyright © 2008 Dorling Kindersley Limited.
Buy this book now!

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