Your pregnancy: weeks 17 to 20
Your baby
Your baby is growing quickly now, about an inch every month. At 18 weeks, your baby will be around 8 inches long and weigh about 8 ounces. The umbilical cord that connects you and your baby is thickening and continues to carry blood and nutrients.
You’ll probably have an ultrasound appointment with us at this stage. We’ll see how you’re feeling, check on your little one’s development, and say “hi” to your baby via ultrasound. Around week 20, we’ll be able to tell you the reproductive anatomy of your baby — unless you want it to be a surprise!
What’s happening this week?

17 weeks pregnant
Fingerprints develop this week. As if I need any more proof that my baby is one of a kind…
- Your baby is almost the size of a pear.
- Their eyes can move slightly from side to side.
- Your little one is starting to develop body fat.
- Tiny knees, elbows, and knuckles can bend, flex, and move.

18 weeks pregnant
No, I’m not talking to myself. I’m talking to my baby! This week, my little one will hear sounds for the first time.
- Your baby is the size of a bell pepper.
- The inner ears are developing, and your baby might be starting to hear sounds.
- Fine, downy hair and a white creamy substance cover your baby’s body, creating a waterproof barrier that protects their skin from drying out in the amniotic fluid.

19 weeks pregnant
Now that my little sweetheart can hear, it’s time to make a playlist for us. Any requests, baby? Just kick if you hear a song you like!
- Your baby is the size of a tomato.
- Little ears can hear your heartbeat, your voice, and loud sounds — like music — from outside your body.
- Your little one’s eyes can sense light.
- Your baby can hiccup and yawn, which you might see if you have an ultrasound this week.

20 weeks pregnant
Imagining how tiny my baby’s hands are. Can’t wait to hold them in mine!
- Your baby is the size of an artichoke.
- Your little one is stretching and kicking more, especially in response to loud noises.
- The fine, downy hair that covered your baby is beginning to disappear.
- Your little one’s heartbeat can be heard through a stethoscope.
Your body
Can you feel your baby moving? Those first flutters are called “quickening,” and some people say they feel like butterflies.
Don’t panic if you notice dark patches on your face. They’re from the extra estrogen your body is producing and should lighten after pregnancy. Just be sure to use sunscreen to prevent the patches from darkening in the sun. (Actually, sunscreen’s always a good idea.) You may also see a narrow, dark line running from your belly button to the top of your pubic bone. All these changes are normal signs that your pregnancy is on track.
Your to-do list
- Schedule an appointment with us between weeks 16 and 20. We’ll measure your baby’s growth and development and get a better sense of your due date.
- If you’re a Kaiser Permanente member, make sure you’re registered on kp.org so you can email your doctor with questions, keep track of your prenatal appointments, and more online.
- Download our pregnancy and childbirth podcast — guided meditation to support you during pregnancy and help prepare you for childbirth.
- Decide whether you and your partner want to hire a personal labor coach (doula).
- Prepare for your baby’s birth by taking a class.*
- If you plan to go back to work, start thinking about child care.
*Some classes may require a fee.