At 29 weeks, your baby is about 38.6 cm to 39 cm long and weighs around 1.25 kg to 1.4 kg, about the size of an butternut squash.
Here’s what’s happening inside:
- White fat is forming under the skin, smoothing out wrinkles and acting as an energy store
- Brown fat, already developed, is helping regulate body temperature
- The brain is growing rapidly, especially in the head
- Muscles and lungs are maturing
- Bone marrow has now taken over red blood cell production, a job previously done by the liver
- The respiratory system is still developing. The lungs are starting to produce surfactant, a substance that helps the lungs stay open after birth. By week 35, there will be enough of it to support breathing.
- The protective layer called vernix caseosa, which has been covering your baby’s skin, is starting to disappear.
- A protective coating called myelin is starting to form around the baby’s nerves. This process will continue after birth.
- Most babies begin to turn head-down, preparing for delivery. You might be able to guess the baby’s position based on where you feel strong kicks (usually legs) and smaller movements (like punches or rolls).
While about 25% of babies are still in breech (bottom-down) position at week 29, only around 3-4% remain in that position by full term.