The First 9 Months – Stages of development

The Third Trimester

The third trimester (weeks 29 – 40) may find you having some of the same discomforts you had in your second trimester. Because the baby is getting bigger and is putting more pressure on your organs, you may find breathing more difficult and notice you have to go to the bathroom even more often. The baby is fine and your problems will lessen once you give birth. As the due date approaches, your cervix becomes thinner and softer (called effacing.) This is normal and natural. This process helps the birth canal (vagina) to open during the birthing process. As you near your due date, the doctor will check your progress with a vaginal exam.

Some of the new body changes you might notice during the third trimester include:

  • Shortness of breath
  • Heartburn
  • Swelling of the ankles, fingers, and face. (If you notice any sudden or extreme swelling or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)
  • Hemorrhoids
  • Tender breasts, which may leak a watery pre-milk called colostrum.
  • Your belly button may stick out
  • Trouble sleeping
  • The baby “dropping”, or moving lower in your abdomen
  • Contractions, which can be a sign of real or false labor.

32 Weeks – Bones are fully formed but still soft and the baby’s kicks and jabs are forceful. The eyes can open and close and changes in light. The lungs are still developing and the baby does practice “breathing” movements. Iron and calcium are beginning to store in the baby’s body and the lanugo begins to fall off. The baby is sleeping 90-95% of the day and sometimes experiences REM sleep, which indicates dreaming.

34 Weeks – At this stage the baby weighs approximately four and one-half pounds and continues to grow and mature. The head is covered in hair, the fingernails have reached the tips of the fingers, and toenails are close to full growth. The lungs are still developing. If the baby is born at this stage, he would probably need some assistance breathing.

36 Weeks – Body fat increases and the baby gets bigger and bigger giving it less space to move around. The movements are less forceful but you will feel stretches and wiggles. The protective waxy coating called vernix gets thicker.

37 Weeks – By the end of this week, the baby is considered full term. The baby’s organs are ready to function on their own.

40 Weeks – As the due date approaches, the baby may turn into a head-down position for birth. Most babies “present” head down. Only about 4% of babies are born on their due date. At birth the baby may weigh somewhere between 6 to 9 pounds and 19 to 21 inches long. These are approximate weights and heights for full term babies, but healthy babies come in many different sizes.