13 weeks pregnant with multiples

Welcome to the second trimester! One down, two to go. Over the next few months, your babies will undergo significant changes. Their organs will develop and grow, and they’ll gain the ability to hear and swallow. You’ll also begin to feel your little ones moving around in your belly! Let’s talk 13 weeks pregnant with multiples.

Many pregnant people report they feel their best during the second trimester. Let’s take a look at what your babies are up to this week, and what you can expect over the next few months. 

What’s going on with your babies?

Your little ones are doing big things behind the scenes! They now weigh about 0.8 ounces and are close to 3 inches long. For a size reference, think of a lemon… or, should we say, multiple lemons. 

Your babies have also begun forming their fingerprints. Fun fact: even if your multiples are identical, they will each have their own unique set of prints. Your babies’ organs and veins are now visible through their skin, which remains translucent. 

At the end of the first trimester, your healthcare provider would have determined whether you are expecting identical or fraternal multiples — or even a combination of both if you’re carrying more than two babies. This trimester, you’ll be able to see the sex of your babies on an ultrasound if you wish to know. 

How are you feeling?

Hopefully, quite a bit better! The second trimester is when most pregnant people feel their morning sickness begin to subside, but it’s normal for it to carry on a bit longer in some cases. If you’re still feeling less than stellar, brighter days should be on the horizon soon.

You’ve also had some time to sit with the news of multiples for a bit, so you may be feeling less shocked and more confident about welcoming more than one baby. Many people feel comfortable announcing their pregnancies in the second trimester, but how and when you share the news is a personal decision. 

Will testing take place this trimester?

If you haven’t already had your first trimester screenings, there’s still time, but you’ll need to make that decision now. The first trimester screening for chromosomal abnormalities is performed between weeks 11 and 14 of pregnancy. This test consists of a blood draw and an ultrasound. The screening helps identify markers for Down syndrome and trisomy 18.

An optional test called chorionic villus sampling, or CVS, can be conducted between weeks 10 and 13 of pregnancy. This screening assesses your babies’ risks of chromosomal conditions, such as Down syndrome and trisomy 18, as well as genetic conditions like cystic fibrosis. The test is more difficult to perform if you have three or more babies because it’s harder to confirm that each sample is from a different placenta. It’s your decision whether you wish to receive this testing, but if you do want the screening performed, remember it must be done by the end of this week.

Additional tests in the second trimester

Multiple marker test

This is a blood test that will be done between weeks 15 and 20 to screen for chromosomal disorders and neural tube defects. Referred to as an integrated screening test, its results are combined with first trimester testing to give a more accurate result. This test may be less helpful if you have two or more babies, so speak to your provider if this is an option for you.


Chances are, you’ve already had at least one ultrasound during your pregnancy. Between weeks 18 and 20, you will receive a “level 2” ultrasound to examine your babies more closely. It will also confirm your babies are developing normally. Because a multiple pregnancy  has higher risk for complications, you may have more than one ultrasound in the second trimester. 

Glucose screening

This blood test checks for gestational diabetes, which is a temporary form of diabetes some people develop during pregnancy. Gestational diabetes can affect  your babies during pregnancy and long term if undiagnosed. To take this test, you will first drink a sugary liquid a lot like flat soda; your blood will  then be drawn to test your glucose levels. You’ll receive this test between weeks 24 and 28 unless you are deemed to be at a higher risk for the condition. 

Reviewed by the Ovia Health Clinical Team


  • American College of Obstetricians and Gynecologists. “Multifetal gestation: Twin, triplet, and higher order multifetal pregnancies.” National Guideline Clearinghouse. U.S. Department of Health and Human Services, May 2014. Retrieved May 15 2021.
  • Mayo Clinic Staff. “Twin pregnancy: What multiples mean for mom.” Mayo Clinic. Mayo Clinic, December 13 2014. Retrieved May 15 2021. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/twin-pregnancy/art-20048161.
  • “FAQ: Multiple pregnancy.” American College of Obstetricians and Gynecologists. American College of Obstetricians and Gynecologists, July 2015. Retrieved May 15 2021.
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