Second Trimester

A space to give you hints about what is happening in the pregnancy and birth world, it’s common problems, and how to solve them

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21 Weeks Pregnant with Twins: Ultrasound, Symptoms, and More

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At 21 weeks pregnant with twins, you’re officially half way through! Of course, since you’re having twins, you’re probably expecting to be due early, so this is more an unofficial halfway mark.

Either way, congratulations! You’re doing amazing. The next few weeks aren’t too bad, as side effects go, and until your babies get significantly bigger, you should still have the energy and mobility to take advantage of how good you’re feeling.

Twin Pregnancy Symptoms at 21 Weeks

A single fetus at 21 weeks

Your Twin Babies at 21 Weeks Pregnant

This week, we switch from measuring your babies from crown to rump (or the top of their head to their tiny little bottoms,) to measuring them from head to toe.

This is because they’ve finally stretched out fully, making measuring them correctly a lot easier.

On that note, round about now, your babies are 10 to 11 inches long, and weigh 11 to 12 ounces. Almost three quarters of a pound!

Your babies digestive system has also kicked into gear, and it’s started producing meconium, or the black stuff that will be in the contents of your babies first diapers.

Not only this, but your babies will have started practising swallowing, and their digestive system will be working. Every day, they’ll swallow a little bit of amniotic fluid, and this teaches their bodies how to process food.

It might sound strange, but you should look at what you’re eating right now, too. The foods you eat will actually show up in your amniotic fluid, changing the flavor, and you can be absolutely sure that your babies can taste it, too! They’ve got almost fully developed taste buds, and studies show that women who eat certain foods can affect their children’s attitudes to those foods later in life.

So eat your greens now, so you don’t have to fight to make them eat their greens later!

Twin Pregnancy Symptoms at 21 Weeks

You’ve hit the second half of your twin pregnancy, and the symptoms that could be coming up in the next couple of weeks are a taster of what you’ll be facing in the third trimester. So learning to live with them now can be a great help.

  • Braxton Hicks contractions: Braxton Hicks contractions are your body practicing for your eventual childbirth. It’s possible to feel them from around the 16th week, but most women tend to start feeling them in the second half of their pregnancy. They should only last 30 seconds at most, and will probably stop if you shift position and move around. They’re absolutely nothing to worry about, and you only need to let your doctor know if they don’t stop after a couple of minutes.
  • Digestion issues: Spicy, sugary and greasy foods can set you off, especially since your digestive system is extra sensitive right now. If you’re struggling, keep a diary of what you eat, and see if you can find a common link.
  • Stretch marks: You’re going to keep getting bigger, especially since you’re having twins, so expect your skin to take the brunt of it. Moisturising and massaging them is supposed to help, but there’s no real way to guarantee that you can rid yourself of them.
  • Leaking boobs: Your boobs should be fully developed by the end of the 24th week and ready for breastfeeding, so if you get a little leakage this early, don’t worry. It’s just a sign that your body has come prepared!

Twin Ultrasound at 21 Weeks

If your mid pregnancy scan was a little late, you might be having it this week instead. Remember, if you’re having your scan a little later, your twins will be slightly more developed than they otherwise might be.

On the upside, that makes any photos and videos you get of the moment even better, so make sure you ask for some mementos.

Things to Do This Week for a Healthy Pregnancy

  • More skin oil might lead to an outbreak of acne in the coming weeks. If it happens, make sure you’re washing your face with soft soap or facial cleansers. Don’t use any acne medication, as it could cause issues with your pregnancy.
  • Make plans for a baby shower. If you need some help, we’ve got everything you need.
  • Talk to your doctor about a glucose screening test. This is normally performed between the 24th and 28th weeks, so you haven’t got long.

Worth Buying Now

Don’t leave your baby shopping too late. Check out our newborn twins shopping list.

Are You 21 Weeks Pregnant with Twins?


You’re over the halfway mark! That alone can hit some women hard, and considering you’re still awash with hormones and probably feeling pretty tired, it’s good to get some help every now and then.

Don’t feel bad about relying on your family and friends from time to time. But if you’ve got any questions you need answering, and no one else has the answer, feel free to drop us a comment, and we’ll do everything we can to help. How do you feel at 21 weeks pregnant with twins?


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