You have made it to the third and last trimester! But the baby still has some developing to do before he/she is ready to meet the world. In the next 10-12 weeks, your baby’s head will triple in size, they will gain more weight, they will rotate to be head down in preparation for delivery, and the lungs will finally fully mature. (1) (2) Let’s take a closer look at some of the specifics of what will happen each week. 


Week 28

     This week, the baby’s eyesight is becoming stronger. (1) The autonomic nervous system, which controls involuntary movements like blinking, breathing, etc., is now able to control the baby’s body temperature and breathing movements. This means the lungs are working and getting stronger. (3)

Week 28 Fun Facts

  • Baby is the size of an eggplant (2)
  • Baby has eyelashes and can partially open their eyes. (2)

Week 29

     The baby’s bones are gradually being strengthened and hardened. There is also a coating called myelin that is forming around the baby’s nerves for protection. (4) This week they are also able to kick, stretch, and make grasping movements with their fists. (1)

Week 29 Fun Facts

  • Baby is the size of a butternut squash (2)
  • Baby’s bones are absorbing 250mg of calcium every day! (4)

Week 30

     This week, the baby’s skin cells are producing melanin. Melanin is what gives the baby’s skin its color, and the more melanin, the darker the skin. (5) Although this process has begun, the baby’s skin will not reach its darkest color until about 6 months of age. (5) 

Week 30 Fun Facts

  • Baby is the size of a large cabbage. (2)
  • Baby could have a full head of hair by now. (5)
  • Baby can now fully open its eyes. (1)

Week 31

     At this point in the pregnancy, most of the major development of the baby is complete. The main priority now is weight gain. (1) The baby is also becoming more active at this point, so you will be feeling more movement. (6)  

Week 31 Fun Facts

  • Baby is the size of a coconut. (2)
  • Baby can summersault. (6)

Week 32

     This week, the baby is starting to store minerals like iron, calcium, and phosphorus. The iron that they store now will last through the first 6 months of their life after birth. (7) This is also the week when the lanugo (peach-like hair that covers their body) will start falling out. (1) Moms will gain about a pound a week at this point, and half of that will go to the baby. (2)  

Week 32 Fun Facts

  • Baby is the size of a large jicama. (2)
  • Baby’s lungs are still not fully formed. (7)

Week 33

     This week the baby’s pupils can now change in size based on light or darkness. (1) The bones are continuing to harden, except their skull bones. These will remain soft so the head can fit through the birth canal. (8) Their skin is continuing to plump and become less wrinkled and transparent. (8) 

Week 33 Fun Facts

  • Baby is the size of a pineapple. (2) 
  • Baby is growing rapidly, so they are not flipping around as much due to less room in the womb. (8)

Week 34

     The growing and fattening continue this week! Also, the fingernails have reached the tips of the fingers. (1) The baby can also now respond to sound, light, and touch. (9)

 Week 34 Fun Facts

  • Baby is the size of a cantaloupe. (2)

Week 35

     This week the baby’s kidneys have fully developed and their first poop (meconium) is building in their intestines. (10) The baby also has regular sleep patterns. You will probably feel them moving around more when they are awake. (10) 

Week 35 Fun Facts

  • Baby is the size of a honeydew melon. (2)
  • Baby’s arms and legs have fattened up! (1)

Week 36

     At this point in the pregnancy, the baby doesn’t have much room in the uterus. (1) The lanugo (peach-like hair) and vernix caseosa (cheese-like substance) continue to shed from the baby’s skin. They will swallow these substances which will help make up their meconium (first poop). (11) 

Week 36 Fun Facts

  • Baby is the size of a head of romaine lettuce. (2)
  • Baby is gaining about 1 ounce per day. (2)


Week 37

     During this week the baby’s head will start descending into the mother’s pelvis. (1) They are still putting on fat and their brain continues to grow. (11) 

Week 37 Fun Facts

  • Baby is the size of a bundle of swiss chard. (2) 
  • You can go into labor any day now! (2)

Week 38

     The baby’s toenails are finally at the tips of its toes. And the fingernails may even be past the tip of the fingers. (12) Most of the lanugo has shed by now and they may have more hair on their head. (12) 

Week 38 Fun Facts

  • Baby is the size of a leek. (2)
  • Baby’s head and abdomen are the same circumferences. (1)

Week 39

     The baby is still putting on fat, even though they are technically full-term. (1) This week their chest becomes more prominent and they have a firm grasp. (13)

Week 39 Fun Facts 

  • Baby is the size of a mini watermelon. (2) 
  • Newborns can see 6-10 inches in front of them. 


Week 40

     At this point, the baby is ready to be born. They will continue to gain weight and will keep moving down into the pelvis until birth occurs. (1)

Week 40 Fun Facts

  • Baby is the size of a small pumpkin. (2)
  • Babies are born with 275 bones, but adults have 206. This is due to some of the bones fusing while growing. (11)

     40 weeks is considered full term, so the baby will most likely be born in the next week or two. You will be meeting your baby soon! If you’re interested in learning more about the labor process, click here.

If you have any questions or concerns, please contact;

Nurturing Center of Lubbock
3303 66th Street
Lubbock, TX 79413
Phone: 806-780-6853 (available 24 hours)
Text: 806-317-4480





Marlee Henn, RN

Marlee has been a nurse for two years and currently works in a functional medical clinic and part time in a long term acute care center. She has a passion for natural living, women’s health, and education.