Week 40 of Pregnancy: What's Going On Inside

Overview

At 40 weeks, you have reached your due date. Your baby could be coming any day.

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.
  • If you don't start labor on your own by 41 or 42 weeks, your doctor may talk to you about your options to start (induce) labor. 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: July 10, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.