Week 12 of Pregnancy: What's Going On Inside


By week 12, you can now hear your baby's heartbeat with a Doppler heart monitor.

Wondering what your baby looks like at 12 weeks? Your baby is now about the size of a lime. Average baby length is 2.4 in. (61 mm).

How your baby is changing

Here are some important changes that happen around this time.

  • By 10 weeks of pregnancy, embryos have nearly all of the body structures that adults have. Their brain is now more complex. After this point, we call this a fetus.
  • During this month, the fetus's limbs, hands, and head start to move. Eyelids cover their eyes, and their fingernails are starting to grow.
  • At the end of this month, fetuses start a big weight gain.


Current as of: February 23, 2022

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
William Gilbert MD - Maternal and Fetal Medicine

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