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Pregnancy Week 40

Fetal Development at week 40

Your Baby

During these last few weeks in the womb, the baby continues to receive one of the most important ingredients for survival from your blood, from the placenta, and also from the amniotic fluid (which is swallowed periodically): disease-combating antibodies that will provide immunity to a wide range of illnesses.

Don’t worry if your baby’s head becomes molded or elongated during the birth process. It will return to its normal, rounded shape a few days after childbirth. The molding is a safety precaution - the bones of the skull carefully slide over one another to reduce the skull’s diameter, so the pressure of the contractions and tight fit through the mother’s pelvis doesn’t damage the baby’s brain.

The first breaths your baby takes are the hardest. It is an effort that can be compared to clearing a snorkel tube that has gotten water in it.

At the end of this week, your baby is considered fully developed. That means that all of the development that takes place before birth has been accomplished.


Most babies drop into a head first, face down position in their mother’s pelvis. In some cases, the baby is in a head first, face up position, so the back of its head presses against the mother’s tailbone or spine. This produces the phenomenon called 'back labor.' The pain of back labor is especially intense and doesn’t seem to let up, even between contractions. A kick from the womb during this stage of pregnancy can almost knock a book off your lap!

As you get to this point, you will find that you have more and more trouble sleeping and getting around. It’s difficult to find any comfortable position, and if the baby is moving frequently or if you are experiencing Braxton-Hicks contractions, you may not be able to sleep even when you are comfortable. Try to relax and rest when you can. It’s difficult to be on any type of routine now.