Seeing Double (or More)? What to Know About a Twin Pregnancy Ultrasound

twin pregnancy ultrasound image of identical newborn twin boys

Learning that you’re carrying twins or more can come as a big surprise. Knowing what to expect during your routine twin pregnancy ultrasounds can help you feel more prepared and excited for your growing family.

The discovery that you’re carrying twins (or more) likely brings with it a whole gamut of emotions. Your pregnancy journey can be more complex since multiples carry a higher risk of complication but knowing what’s ahead, especially during the ultrasound process, can help ease any apprehension you might be experiencing.

This article will discuss:

  • How to tell if you’re having multiples
  • The ways multiples appear on ultrasounds
  • How many ultrasounds you typically need
  • Any complications that might arise
  • How to prepare for your ultrasound appointment
  • How to view and share your ultrasound results

How do you know if you’re pregnant with twins or multiples?

Your first prenatal ultrasound is when you’ll most likely discover you’re pregnant with twins or multiples. The first ultrasound of your pregnancy, usually performed between 6-14 weeks, will determine both the viability and the number of embryos you are carrying. Ultrasounds in your first trimester are also sometimes called ‘dating scans’ because they narrow down the due date and the gestational age.

In an ultrasound, a transducer rod transmits sound waves into the body at a frequency hundreds of times higher than humans can hear. The echoes of those sound waves are recaptured and processed to produce images and reports. The U.S. Food & Drug Administration considers prenatal ultrasounds to be low-risk exams, with an excellent safety record for more than 20 years.

How early will an ultrasound show twins or multiples?

If you have an ultrasound as early as 6 or 7 weeks, you’ll likely be able to identify whether you’re carrying multiple embryos. By the 10-week mark, the scan will be clear enough to discern what type of twins or multiples you’re carrying.

What do twins or multiples look like on ultrasound?

Your embryos’ appearance will depend on the kind of twins or multiples you’re having. Identical twins or triplets come from a single fertilized egg that splits into two or three, and are truly genetically identical. Fraternal twins or triplets come from two or three different eggs, each fertilized by different sperm. Depending on the type, the embryos might share a gestational sac, placenta or amniotic sac. Here’s a breakdown of the types of mulitples:

  • Mono-mono: These identical twins or triplets share the same placenta and amniotic sac. This is the least common type of twin and very rare for triplets.
  • Mono-di or mono-tri: These identical twins or triplets share the same placenta but each have their own amniotic sac.
  • Di-di or tri-tri: These multiples can be either identical or fraternal, and each will have its own placenta and amniotic sac.
  • Di-tri: Two of these triplets will be identical and one will be fraternal. The identical triplets will share a placenta, but each have their own amniotic sac, while the fraternal triplet will have its own placenta and amniotic sac.
identical twin pregnancy ultrasound labeled image

Ultrasound image of identical mono-di twins

fraternal twin pregnancy ultrasound labeled image

Ultrasound image of fraternal di-di twins

How many ultrasounds do you get when pregnant with multiples?

Twins and triplets are generally considered higher-risk, so you’ll likely have more ultrasounds than usual throughout your pregnancy to monitor fetal health and development, especially leading up to your delivery.

Since twin embryos are generally smaller, it’s possible to miss them in early ultrasounds. With a hidden twin, one twin might block the other from view, especially among twins who share an amniotic sac. As they grow, however, the likelihood of missing sight of one of them declines.

What weeks of pregnancy are ultrasounds done?

The usual prenatal ultrasounds include a dating scan somewhere between 10 and 14 weeks, and an anatomy scan between 18 and 22 weeks. These ultrasounds confirm your pregnancy, monitor the fetal heartbeat, determine the gestational age and sex, and observe general growth and development.

You may also have an optional nuchal translucency (NT) ultrasound between 10 and 13 weeks. The NT measurements taken during this ultrasound evaluates the risk of Down syndrome and other congenital abnormalities.

When you’re pregnant with twins or multiples, you’ll likely have several additional scans, including:

  • Chorionicity ultrasound to find out whether each fetus has its own chorion (one of the membranes that surround a forming fetus) and amniotic sac to determine types of multiple you’re carrying. This scan usually happens around 10 weeks.
  • Doppler ultrasound to measure blood flow from the placenta through the umbilical cord and assess whether all the embryos are getting enough food and oxygen. This is performed if one twin or triplet appears bigger than the other(s).
  • Cardiotocograph (CTG) to monitor your babies’ heartbeats. CTGs are another type of Doppler scan, and may be used to monitor the fetal heart rate during late pregnancy and labor.
  • Growth scans in your second and third trimesters, to track progress and check your babies’ growth. These may be recommended every 2-6 weeks, depending on your circumstances.

Complications that can arise during twin or multiples pregnancy

While being pregnant with multiples carries a higher risk, rest assured that your healthcare team is constantly monitoring your health, as well as the health and development of your babies. It’s why so many ultrasounds are performed throughout a twin or multiple pregnancy: to check for any potential complications and avoid any adverse outcomes.

Risks that your healthcare team are actively monitoring for, include:

  • Umbilical cord entanglement, which could impede the flow of blood and nutrients or cause difficulty during birth. However, this is usually only cause for concern in mono-mono-twins (share placenta and amniotic sac), which occur in only 1% of identical twin pregnancies.
  • Twin–twin transfusion syndrome (TTTS), a rare condition in mono-di twin pregnancies (who share a placenta), in which one twin shares more blood than it receives to the detriment of both.
  • Vanishing twin, which is when embryo is lost after having been confirmed in an earlier scan.
  • Preterm labor, or when twins or multiples are born before 37 weeks of gestation. While 60% of twins and almost all triplets and higher multiples are born premature, this is normal and to be expected. Triplet and higher multiple pregnancies often have a preterm delivery around 28-30 weeks, while twins are typically delivered between weeks 32-36.
  • Preeclampsia, very high blood pressure after week 20, is 2-3 times more likely if you’re pregnant with multiples than with a singleton. You’re also twice as likely to develop anemia or hypertension while carrying multiples.

Although many deliver twins vaginally, C-sections are more common with multiples than in singleton births and are often scheduled in advance. This is to ensure that your healthcare team can control the labor and delivery process. Due to the preterm delivery, twins and multiples may need to spend time in the NICU before returning home.

How to prepare for a twin pregnancy or multiples ultrasound

There are two main types of pregnancy ultrasounds: transabdominal, in which the technician coats your belly with lubricant and runs the transducer wand through it; and transvaginal, in which the lubricated transducer wand is inserted in the vagina. There are a few things you can do to prepare for your ultrasound:

  • Bring a copy of your requisition: your requisition will specify exactly which type of exam you need. Having it with you will streamline your check-in process if your practitioner didn’t send it to the imaging clinic or hospital ahead of time.
  • Know which type of ultrasound you’re getting: transvaginal ultrasounds are typically performed in early pregnancy. Since the embryos are so small, the transducer can capture more details and images from inside the vaginal canal.
  • Wear loose and comfortable clothing: make sure to wear clothes you can easily get in and out of.
  • Drink lots of water in the week leading up to your appointment: when you’re well-hydrated, your amniotic fluid is clear, which makes for better images.
  • Book your appointment when your babies are most active: movement helps the technician capture more images. Another trick is to drink something cold and sugary just before your appointment.
  • Arrive with a full bladder: Sound waves travel well through liquid, which makes it easier for the sonographer to capture the images you need.
  • Have a support person join you: It often helps to have a support person with you, but check ahead of time. Not all hospitals or imaging clinics allow someone to accompany you in the exam room.

Questions to ask during and after your ultrasound

To stay fully informed on your pregnancy journey, don’t hesitate to ask the sonographer or technician questions before or during the appointment. You can ask about the procedure itself and everything that surrounds it, like:

  • How long will the appointment last?
  • Can anyone join me during the ultrasound? How many people?
  • Can I take my own photos and videos during my appointment?
  • How can I access and share my images/results?
  • When will my practitioner receive the results?

The sonographer, who cannot legally discuss the results of your ultrasound with you, will prepare the images for a radiologist to review. The radiologist will interpret the images and send a report to your referring practitioner. You’ll get the results during a follow-up appointment and can ask different questions then, such as:

  • Am I having twins? Triplets? Or more?
  • Can we see all the embryos? Are they the same size?
  • How many placentas are visible?
  • What type of multiple (mono-mono, di-di, etc.) am I expecting? If it’s too early to tell, when will we know?
  • How will my pregnancy differ from a singleton pregnancy?
  • What other tests are recommended? Are those tests standard or optional?
  • Are there any complications I should be aware of? If so, how will we monitor them going forward?
  • Do I need to see a specialist?
  • What changes should I make to my diet?
  • What does this mean for my delivery?

How quickly can you get your ultrasound images and results?

If you want faster access to your medical records, whether it’s to see the report prior to your doctor’s appointment or to share the scan images with your family and friends, you can use PocketHealth. Access your records here.

With PocketHealth, you can securely access and permanently store your images and other health information all in one place. You can also use PocketHealth to conveniently share your ultrasound images with loved ones so they can easily see how your pregnancy is progressing.

If you find any of the terminology confusing in your ultrasound report, PocketHealth Report Reader can help. Report Reader provides easy-to-understand definitions of the terms in your ultrasound report so you can feel confident when discussing the results with your practitioner.

Getting ready for your double-feature

Finding out you’re having twins or multiples can be a lot to process and knowing you’re now having what’s considered a high-risk pregnancy can heighten your stress. But you can take comfort in knowing the additional ultrasounds will help ensure you and your babies are healthy and developing well leading up to delivery. Being prepared for what’s ahead in your unique pregnancy journey can help you feel more confident and in control.

How PocketHealth works

Learn more about how to use PocketHealth to access and share your twin pregnancy ultrasound records.

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