Weekly Guide to Pregnancy: Week 40

Week 40
Week 40 

Your Baby

How big is my baby?

Fetal size: crown-rump 37-38cm (14.8-15.2 inches), crown-toes 48cm (21.5 inches). Fetal weight: 3.4kg (7.5 pounds).

If your baby hasn't already been born, he/she is preparing to be born. By the end of this week your baby is fully mature and all organs are developed and working ready for life outside the uterus. Your baby will also be plumper, and will need to curl up to fit inside your uterus. You will still be able to feel your baby kicking, but the increasingly limited space in your uterus will mean movements are much less than they were a few weeks ago.

By now your baby should have "engaged" or moved into a head down position ready for birth. When engaged, your baby's head settles deeply into your pelvis, resting against your cervix.

Your baby's skin is now much smoother. When awake, your baby's eyes are open, and will probably be blue when he/she is born. If the eyes are going to be a colour other than blue, they will change within a few weeks of birth. Your baby's fingernails are long, and it won't be long before they need a trim. The lungs are maturing in preparation for breathing air outside the uterus.

Your baby's immune system still needs to mature. Until it does, he/she receives your antibodies through the placenta. Breast milk is also an important source of antibodies for your baby after he/she is born, particularly colostrum, secreted for the first few days before your milk comes through.

Your baby will get rid of bilirubin (breakdown product from red blood cells) before he/she is born. Bilirubin will be transferred from the fetus, across the placenta, through to your blood circulation. After your baby is born, it will be able to handle the bilirubin its body produces on its own.

Your baby's intestine is filled with a dark green to black substance called meconium. After your baby is born, this will be the first bowel motion he/she passes. Sometimes babies pass meconium during delivery.

Your Pregnancy

What pregnancy symptoms will I be experiencing?

You will probably start to see your health professional on a more regular basis (usually weekly) during the weeks leading up to the birth of your baby. During this time you may also experience the "nesting instinct", translating to a desire to clean the house or make things ready for the baby. Don't overdo it - you'll need lots of energy for the birth. This week you should be resting if possible.

When your baby engages, you will feel a bit more comfortable, mainly because your baby drops a bit and some of the pressure is taken off your diaphragm. Because you are carrying so much weight at the front of your body, you may tend to lean back more. This may result in clumsiness, so be careful and take it slowly.

Getting a good nights sleep is probably quite difficult now, as your size makes it hard to get comfortable. If you're not sleeping well, try to rest as much as possible during the day.

You may find that your breasts begin to get swollen as the placenta starts to produce the hormones that stimulate milk production.

By now you are eagerly anticipating the birth of your baby - if only because you are so uncomfortable! If your baby doesn't come by your due date, your health care professional may wait for up to 14 days for you to go into labour naturally. If you reach 42 weeks, most health care professionals will agree that the baby should be delivered if it is in the proper presentation. You may be monitored for another few days in the hope that you will go into natural labour, or your health care professional may discuss the possibility of inducing labour or performing a caesarian section.

Learn more about your pregnancy

Read more information on Pregnancy and Birth on Essential Baby.

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