Week 20 of Pregnancy: What's Going On Inside

Overview

By week 20, you've probably felt your baby move. It may not feel like an obvious kick—yet! Instead, your baby's first movements might feel like "butterflies" or gas bubbles.

Inside the uterus, your baby is enjoying some regular activities: thumb-sucking and opening and closing his or her eyes.

Wondering what your baby looks like at 20 weeks? Your baby is now about the size of a red pepper. Average baby length is 6.3 in. (160 mm).

How your baby is changing

Here are some of the important facts and developments around 20 weeks.

• This is a time of very rapid growth, especially from 15 to 18 weeks of pregnancy.
• By now, babies' heads are no longer so big compared to the rest of their body.
• You can see bones on ultrasound by the end of week 17.
• At this size, your baby is still small enough to change position a lot—from head-down to feet-down, or even sideways.
• If this is your first pregnancy, you will start to feel your baby move. The first flutters you feel are called "quickening."
• At the end of this month, your baby starts building up body fat.