Your developing baby – week 33

by Kaiser Permanente |
Fetus at week 33, illustration

It’s almost showtime! At week 33, your baby is around 17 inches long and about the size of a spaghetti squash. This week your baby:

  • Acts more like a newborn. They close their eyes when sleeping and open them when awake.
  • Is growing rapidly and filling your uterus and the amount amniotic fluid surrounding the baby is decreasing. This means that you might feel sharper kicks and movements from your little one.

Your baby’s immune system is now developed. Your body passes antibodies to your baby, which helps the baby fight infections after birth.

Over the next weeks, your baby’s: 

  • Bones will harden, but the skull remains soft and flexible.
  • Fingernails will have grown to the end of the fingers.
  • Limbs begin to look chubby.
  • If they haven’t already, your baby may turn into a head-down position for birth.

This article has been created by a national group of Kaiser Permanente ob-gyns, certified nurse-midwives, pediatricians, lactation consultants and other specialists who came together to provide you with the best pregnancy, birth, postpartum, and newborn information.

Some of the content is used and adapted with permission of The Permanente Medical Group.