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21 Weeks Pregnant: Week-by-Week Guide
4 mins read

IN THIS ARTICLE – At this stage of your journey, new developments are beginning to unfold. Check out this week-by-week guide to find out what’s in store for your baby and your body in week 21 of pregnancy.


Your baby at 21 weeks pregnant | Week 21 pregnancy symptoms | 4 expert tips for a healthy and safe pregnancy | Week 21 checklist: How to plan your pregnancy



  • What trimester is 21 weeks? Second trimester
  • How many weeks of pregnancy are left? 19 weeks
  • How many months is 21 weeks pregnant? You are five months pregnant.

One of the most magical things about pregnancy is how much changes with your little one and you over the span of a week! Here’s the best info to keep on top of all that’s happening.

Your baby at 21 weeks pregnant

What's happening in there

  • Your baby is the size of a long banana.
  • You’re in the middle of the second trimester and are almost six months pregnant.
  • The countdown continues: you’ve got 19 weeks to go!

What happens during the 21st week of pregnancy?

  • Make the connection: With your baby’s cognitive development humming along, those billions of neurons are connecting to muscle, allowing your baby to come more active. You may feel those effects. Most future mamas feel babies start to move from 16 to 24 weeks, but if you’re a first-time mom, you might not have felt movements until now.
  • Strong bones: Cartilage throughout your little one’s body is turning to bone, and those bones are continuing to grow and get stronger each day.
  • A blood cell factory: Now that the bones are formed, they start to produce red blood cells in the bone marrow, ready to transport oxygen around the body for the second half of the pregnancy.
  • Getting ready to feed: While most of the nourishment comes through the placenta, your baby can now swallow and digest amniotic fluid and pass waste to the large bowel.

What should I be feeling at 21 weeks pregnant?

  • You’ll have some days feeling beautifully curvaceous, and others just feeling bloated and over it. Ride those waves, you’re halfway there.
  • Your little baby will likely be pushing and kicking, ranging from gentle pokes with their hand to giving some enthusiastic kicks—perhaps soccer stardom is in their future!
  • If you haven’t already had it, you’ll be due for your ultrasound, where you will get a good look at your little creation–including finding out the sex of the baby!

How big is your baby at 21 weeks pregnant?

 21 Weeks Pregnant

Baby Weight

11 ounces

Baby Length

7 inches

Baby Size

Comparable to a long banana


Week 21 pregnancy symptoms

During week 21 of pregnancy, your body is changing quickly. As your baby grows, you will too, and there are certain pregnancy symptoms you may experience at this time.

4 common week 21 pregnancy symptoms

  • Braxton Hicks contractions may start to happen–it’s your uterus tightening and loosening as it gets prepped for labor.
  • Now your breasts are ready for feeding. As a result, you may get leaky nipples.
  • Your hair and nails will probably be growing faster. Enjoy those luscious locks!
  • The extra weight you’re carrying right now can cause backaches and pains, so keep off your feet and your legs elevated when you’re sore. Trying some pregnancy-safe workouts can also help alleviate back pain.

4 expert tips for a healthy and safe pregnancy

Being 21 weeks pregnant is an important time for you and your baby. Here’s some expert-recommended advice on how to adjust to this new stage and keep you and your baby safe.

  1. Get in those greens: What you eat when you’re pregnant can give your baby a taste for good, healthful foods like fruits and vegetables, as the flavors wind up in the amniotic fluid your little one is swallowing–this can contribute to developing a liking for them after birth.
  2. Opt for a balanced plate: In a recent study , women that ate well during pregnancy—i.e., women that ate a diet including plenty of vegetables, fruits, whole grains and water—had a much lower risk of preterm delivery. Trying out some healthy recipes can help provide variety for you and your baby.
  3. Plan your leave: The government entitles most new parents to 12 weeks of unpaid leave. If you haven’t already, find out your employer's policies on paid leave or disability.
  4. Practice seat belt safety: Wear the three-point seat belt so the lap belt is under your belly (not across it), and the shoulder strap is between your breasts.

Week 21 checklist: How to plan your pregnancy

Knowing what to do week-by-week can help you feel prepared and alleviate stress. Add these items to your to-do list this week. You’ve got this, mama! 

To-Do Checklist
Spend some time planning what you’ll need for the nursery.
Haven't decided on a name? Maybe it's time to cull some of them off that ever-growing shortlist.
Take some time out just to be a couple, like a "babymoon", date night or even just a picnic.


Learn more about your pregnancy, including pregnancy planning and pregnancy nutrition to feel prepared to continue this magical adventure. You’re armed with the facts, what to do, and now you can take time to connect with the little one growing inside you. Read about what’s coming up in week 22!

Join Enfamil Family Beginnings

It’s your 21st week of pregnancy, and you and your baby are experiencing exciting changes every day. Prepare for your new arrival with help from Enfamil Family Beginnings. It’s the perfect resource for new and expecting moms. Save on Enfamil products, track your bump and baby’s growth, and get helpful articles each week relevant to your journey. Join now for up to $400 in free gifts.

All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.