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Week 40 of Pregnancy: What's Going On Inside

Overview

You may have felt ready for baby to come for a while, but your baby may still be perfectly happy inside. It can be very hard to wait to meet your baby!

Wondering what your baby looks like at 40 weeks? Your baby is now about the size of a small watermelon. Average baby length is 20 in. (50 cm). And average baby weight is 8 lb (3400 g).

How your baby is changing

Here are some of the important facts and developments around 40 weeks.

  • Your baby is full-term.
  • By the time a baby is born at term, fat makes up 16% of body weight. The baby's growth has slowed in the last days before birth.
  • At this size, your baby does not have much room to move around. You will probably notice less "big" movement than before.
  • Your pregnancy is called "post-term" or overdue when you have reached 42 weeks of pregnancy. This is 2 weeks after your due date. Risks go up for the baby, so delivery is recommended.

Credits

Current as of: February 23, 2022

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
William Gilbert MD - Maternal and Fetal Medicine