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Pregnancy Week 31

Fetal Development at week 31

Your Baby

Your baby’s head-to-bum measurement is now about 11 inches (280mm) - almost as tall as a 12-inch ruler. Its weight is at least 2 3⁄4 pounds (1,300g), more than a four-pint bottle of milk.

Baby’s growth in height and weight will begin to slow between now and birth. Even so, your baby will gain about two pounds (896 g) this month.

If your baby is born now, it may have a callous on its thumb from sucking it in the womb.

For about the last month, your baby has assumed the fetal position in your uterus. The legs have been drawn into the chest because there isn’t room for them to straighten out.

The baby’s brain is still developing rapidly, increasing the number of interconnections between individual nerve cells and identifying groups of cells that will perform complicated functions throughout your baby’s lifetime.


You will continue to notice strong, methodical activity from the baby. Sometimes it seems as though the baby is more active at night than at other times. This may be the case, but it may also be that you simply notice the movements more because you are less distracted by other things.

Your doctor or midwife may order more blood tests for you sometime during this month to make sure your pregnancy is progressing well.

There are four layers of tissue in the placenta separating your blood supply from your baby’s. Unless some breakdown of the placenta occurs, the baby’s blood does not mix with yours.

You may notice that you’re a little clumsy these days. This is due to the increased size of your uterus, the loosening of your joints to prepare for childbirth, and the shifts in the baby’s position.