Baby Development 3rd Trimester Highlights

At last your baby is ready for birth. Over the past three months, your baby has gained fat, muscle tone, and mature lungs. Your baby is ready to kick, to cry, to smile, and to grasp your finger in his tiny fist! At the end of this trimester, your baby has:

  • Muscle tone from moving all about
  • Eyelids that open -- complete with eyelashes
  • Toenails
  • A sweet smile
  • The ability to kick, grasp, and stretch!
  • Eyes that open and close and respond to changes in light
  • Possibly, a full head of hair
  • Fully formed heart, brain, and nearly all other organs and body systems
  • Testes that have descended into a baby boy's scrotum
  • Fingernails that reach to the end of the baby's fingers
  • About 16% body fat
  • Pink, smooth skin and chubby legs
  • Bones and muscles ready for the outside world
  • Lungs ready to breathe and cry
WebMD Medical Reference Reviewed by Traci C. Johnson, MD on January 15, 2019



ACOG: "Your Pregnancy and Childbirth."

Moore: "The Developing Human."

Phillips, J. Pathology, October 2009.

© 2019 WebMD, LLC. All rights reserved.

Get Pregnancy & Parenting Tips In Your Inbox

Doctor-approved information to keep you and your family healthy and happy.

By clicking Subscribe, I agree to the WebMD Terms & Conditions & Privacy Policy and understand that I may opt out of WebMD subscriptions at any time.