Pregnancy Week by Week
10.5
inches
12.7
ounces
BABY IS AS BIG AS AN
ENDIVE

21 Weeks Pregnant

Pressure’s on! Have you found the perfect baby name yet? It seems like parents-to-be either come up with baby’s name quickly and easily, or agonize over it all the way up until the birth. If you haven’t picked that perfect name yet, check out The Bump’s extensive lists of baby names of all sorts; cool names, beautiful names, hipster names and much more. Whatever name you choose, you’ll probably think it’s even more perfect once you get to know (and fall in love with) your future little bundle of joy. At 21 weeks pregnant, you’re not just choosing a name, you’re hard at work getting your home ready too. Of course, things like baby bouncers and changing table pads can be tough to choose, but try not to stress about it at week 21 of pregnancy. Trust us, baby won’t care if you pick out a Pack ‘n Play that clashes with the area rug!

How Big Is Baby at 21 Weeks?

At 21 weeks pregnant, baby is as big as a head of endive. At 10.5 inches and about 12.7 ounces, baby is big enough now that you've probably been feeling their fetal movements more and more lately. Keep in mind that at 21 weeks, baby size is now measured in full body length, rather than crown to rump, so you can get a real idea of how big your baby is at 21 weeks pregnant!

21 Weeks Pregnant Is How Many Months?

Twenty-one weeks pregnant is five months pregnant, although doctors track pregnancy by week, not month. Since pregnancy is 40 weeks long, you’re now a majority of the way through your pregnancy!

21 Weeks Pregnant Symptoms

Common 21 weeks pregnant symptoms are kind of like a sneak preview of the third trimester. Here’s what you might be feeling at week 21 of pregnancy:

  • Heartburn and/or indigestion. Avoid spicy and greasy foods and other triggers to control your heartburn and indigestion. If the source of your discomfort is a mystery, keeping a food diary could help you figure it out.
  • Braxton Hicks contractions. Your uterus might occasionally feel tight as it practices for labor. Braxton Hicks at 21 weeks are totally normal as long as the contractions go away when you switch positions. Let your doctor know about any pain or contractions that don’t stop.
  • Leaky boobs. Your milk ducts will be fully developed by the end of this trimester—just in case of an early arrival—so you may experience some leaking from your breasts.
  • Dry, itchy skin. Your skin is stretching over your growing bump, making it drier and more irritated by the day. Lather up with a pregnancy-safe body oil or lotion to help your skin stay moisturized and hopefully less itchy. Also, if you develop a rash, let your doctor know right away, since that could be a sign of an annoying pregnancy condition called PUPPP.
  • Stretch marks. Your skin gets pulled thinner as baby grows, causing tiny tears beneath the surface of your skin. Stretch marks are more common for some women simply because of family history or because of sudden weight gain. They are also more common in women who are 21 weeks pregnant with twins. There’s no way to truly get rid of stretch marks, but they should fade significantly after birth.

When should I worry about Braxton Hicks at 21 weeks?

You shouldn’t worry at all unless the contractions don’t stop after a couple minutes, get stronger and closer together or there’s fluid or bleeding from the vagina. In those cases, call your doctor. Otherwise, Braxton Hicks contractions are prepping your uterus for all that hard work contracting during labor. Braxton Hicks at 21 weeks are normal but usually just periodic. They rarely last more than two minutes and are often brought on by sex and orgasm, a full bladder, dehydration or a big kick from baby.

21 Weeks Pregnant Belly

This week, you may look in the mirror at your 21 week baby bump and wonder, “Where did I go?!” By the time you reach 21 weeks pregnant, you may have gained around 13 to 14 pounds, and around 21 pounds if you’re 21 weeks pregnant with twins.

Your newfound curves might have you feeling super sexy and confident—after all, you’re the center of attention wherever you go! But the extra weight also might have you feeling self-conscious. Remind yourself, you’re supposed to be gaining this weight and do your best to embrace those curves! It’s good for you and for baby.

In fact, all the weight you gain during pregnancy isn’t just padding for baby—it all serves a really important purpose. Here’s a logical way to think of it: Of the approximately 30 pounds you’ll gain throughout your pregnancy, there’s a whole lot more than fat. Here’s what makes up that weight:

  • An average full-term baby = 7.5 pounds
  • Placenta = 1.5 pounds
  • Uterus = 2 pounds
  • Amniotic fluid = 2 pounds
  • Maternal stores of fat, protein, and other nutrients (needed for breastfeeding!) = 7 pounds
  • Breast tissue (also for breastfeeding, of course) = 2 pounds
  • Increased fluid volume = 4 pounds
  • Increased blood volume = 4 pounds

See? All those pounds are doing a lot of good, keeping baby alive and healthy—and storing up good stuff to nourish them after birth. Anytime you’re feeling a little meh about your body, think of all the amazing things it’s doing!

What to Expect at 21 Weeks Pregnant with Twins

If you’re 21 weeks pregnant with twins, your belly is getting tight, itchy and dry, and you may have already developed some stretch marks. Keep rubbing that 21 week baby bump with plenty of lotion to ease the itchiness. Heartburn is probably a close personal friend at this point too, so watch what you eat to make sure you don’t make it worse, and keep meals smaller and more frequent. If that doesn’t do it, talk to your doctor about a pregnancy-friendly antacid.

21 Weeks Pregnant Ultrasound

Wondering what’s going on with your 21-week fetus? As baby's digestive system preps for the outside world, they’re manufacturing meconium, the tarry black substance you'll find in the first dirty diaper.

Bet you hadn’t even thought about future grandchildren yet, but the reproductive system is developing too. If it's a girl, she's already got a lifetime supply of eggs in her womb—about six million of them! Having a boy? His testes are still located in his abdomen but will drop in the coming weeks once the scrotum finishes developing.

You’ll get a glimpse of that cute little 21-week fetus if you have your mid-pregnancy ultrasound this week. This 21 weeks ultrasound will amaze you! Not only will you get to see baby on the screen, you’ll also get to see some awesome details like the brain hemispheres and chambers of the heart. Let your technician know whether or not you want to know baby’s sex.

Finding out whether it’s a boy or a girl is a pretty exciting moment! But you can also save it for later if you want. Some parents-to-be wait until baby is born to know the sex. Or you could ask the technician to write it down and put it in an envelope so you can take it home. Then, you could plan a gender reveal party, where you can find out the surprise while surrounded by your family and friends. Fun!

At 21 weeks pregnant, pictures of baby are bound to be adorable! Ask for lots of printouts of the pictures, because if you have an uncomplicated pregnancy, this may be the last medical ultrasound you’ll get during pregnancy. Now go show off those photos of your cutie! And keep brainstorming those names!

What is baby doing at 21 weeks in the womb?

Now, at 21 weeks, fetal movement is noticeable—and baby has reflexes too! If you gently press your palm on your belly, you might feel a little push back. So cool! Baby at 21 weeks is practicing coordinated movements and enjoying the room they currently have in your uterus, which means they also need 12 to 14 hours of sleep every day. Baby at 21 weeks is also practicing swallowing amniotic fluid (don’t worry, it’s just practice—baby still gets everything they need through the placenta) and growing taste buds as well as head and body hair.

Tips for 21 Weeks Pregnant

Drink your water
Water can help with 21 weeks pregnant symptoms. As counterintuitive as it may seem, staying hydrated keeps your body from retaining water; it also helps calm those Braxton Hicks contractions and is your best bet for fending off UTIs.

Keep moving
Exercise may sound like a chore right now, but it’ll help with swelling and circulation. Try prenatal yoga, an easy walk or swimming if that belly is feeling extra heavy these days.

Sign up for classes
If you’re interested in taking childbirth classes, breastfeeding classes or infant care classes, now is the time to sign up if you haven’t yet. Classes often fill up early, so get them on the books before your final month.

Pregnancy Checklist at 21 Weeks Pregnant

Reminders for the week:

Medical content was reviewed Novemember 2020 by Patricia Pollio, MD, a New York-based ob-gyn and director of the department of obstetrics & gynecology at Good Samaritan Hospital in Suffern, New York.

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