Week 12 of Pregnancy: What's Going On Inside
Overview
By week 12, you can now hear a fetus's heartbeat with a Doppler heart monitor.
Wondering what a fetus looks like at 12 weeks?
It is now about the size of a lime.
How a fetus is changing
Here are some important changes that happen around this time.
- By 10 weeks of pregnancy, an embryo has nearly all of the body structures that adults have. Its brain is now more complex. After this point, we call it 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.
Credits
Current as of: July 15, 2025
Current as of: July 15, 2025