At 13 weeks, your baby is about 3.5 inches long around the size of a plum. By the time you reach week 13, the placenta has fully formed and begun providing your baby with nutrients and oxygen. It also removes the baby’s waste.
- Veins and internal organs appear through the baby’s nearly see-through (transparent) skin.
- Muscles and bones continue to develop and strengthen.
- Arms and legs are long and thin. Fingerprints have formed on the baby's tiny fingers.
- Hearing starts to develop.
Around week 13, your baby’s able to:
- Make a fist with each hand.
- Put a thumb in the mouth and make a sucking motion.
Your baby has more muscle tissue and harder, more developed bones. Your little one is starting to roll, kick, and move around a lot — flexing tiny arms and legs, too. You may be able to start feeling these movements around week 18.