What to Expect at Your 12-Week Ultrasound

 

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The first day of school. Getting a driver’s license. Buying a house. Life involves many significant milestones. And when you’re pregnant, one of the very first milestones is getting to see your child on an ultrasound.

A positive pregnancy test and plenty of morning sickness are proof enough that you’re pregnant, but your first ultrasound — often around 12 weeks — provides a different kind of evidence that you’re growing a baby.

Like many milestones, your first ultrasound can bring about all the feels. You may feel excited or anxious. You may be grinning from ear to ear or getting a little teary eyed. Whatever you’re feeling is OK!

It’s important to receive this prenatal care. It can provide important information to you and your doctor. If you’re nervous or just curious about what to expect, we’re here to provide answers to your questions.

The 12-week ultrasound helps your doctor make sure you’re getting the appropriate care for the rest of your pregnancy. It also provides them with:

  • an estimated due date
  • information about how many babies to expect
  • information about the possibility of certain genetic disorders

Traditionally, unless you were at high risk for certain pregnancy complications, your doctor might not recommend an ultrasound before 12 weeks. However, doctors today may recommend ultrasounds as early as 6 or 7 weeks — so this might not be your first time seeing baby on the big screen.

Either way, by 12 weeks, your baby will be big enough for your doctor see a ton of useful info that may not have shown up clearly before.

You’ll want to have a full bladder for your 12-week ultrasound. (This helps the sound waves move better and create clearer images.) A good way to ensure this is to empty your bladder, then drink 2 or 3 (8-ounce) glasses of water in the hour before your ultrasound.

Before your ultrasound, you should also perform any bloodwork your doctor may request.

The 12-week ultrasound is usually an external scan. (In occasional cases, an internal — known as transvaginal — scan may be necessary if the external scan can’t produce a clear image.)

You’ll lie back on the exam table, and an ultrasound technician will apply a clear gel across your lower belly. Then, they’ll use a wand on this area to project a picture of your organs onto a screen. They may also take a short recording of your baby’s heartbeat.

The exam should take about 30 to 45 minutes, depending on the position of your baby. It shouldn’t hurt — but depending on how long you’ve been holding your pee or asked to stay in certain positions, you may need to request a minute to shift around and get comfortable again!

Ultrasounds rely on soundwaves and don’t use radiation like X-rays. There’s no current research to indicate that ultrasounds are harmful to a developing baby.

However, the American College of Obstetrics and Gynecologists (ACOG) recommends sticking only to those ultrasounds that are medically required. In a standard pregnancy, this includes the 12-week ultrasound and the 20-week anatomy scan.

If you have a more complicated pregnancy, your doctor may recommend more ultrasounds.

During the 12-week ultrasound, your doctor will:

  • estimate the gestational age and due date (if it’s your first ultrasound)
  • screen for some chromosomal disorders, like Down syndrome
  • count the number of fetuses (singleton, twins, etc.)
  • listen to your baby’s heart rate

While you may be dying to know the sex of your baby, chances are you won’t be able to see this in scans just yet. You’ll also need to wait until the anatomy scan (around 20 weeks) to get more detailed information about how your baby’s organs are developing.

If twins are visible at your 12-week ultrasound, the sonographer will perform a chorionicity scan to determine if the twins share a placenta.

Twins who share a placenta are called monochorionic twins and are always identical. They’re at greater risk for:

If the twins are monochorionic, the sonographer will also check about the amnionicity. This is important, because mo/mo twins (those who share both a placenta and amniotic sac) will require more monitoring to ensure there’s no cord entanglement or compression.

Dichorionic twins have their own separate placentas. These account for all fraternal twins and about one third of identical twins. Because each fetus has its own separate space to develop, these twin pregnancies typically carry the lowest risk of complications.

Twin babies don’t tend to be much smaller than singletons early in pregnancy. If your sonographer notices a size difference between your twins, the larger baby can be used to date the pregnancy in most cases.

There’s a very small chance that a twin may be hiding and missed during your first ultrasound (especially if you have it done earlier than 12 weeks). Chances of missing a twin are higher if they share the same amniotic sac.

After your 20-week anatomy scan, you can pretty much rule this out, though.

At 12 weeks, your doctor can screen for Down syndrome, trisomy 13 (Patau syndrome), and trisomy 18 (Edwards syndrome). This is called nuchal translucency screening.

It requires a combined test: a blood test and a measurement of the fluid at the back of the baby’s neck with the ultrasound.

It’s important to note that this isn’t a diagnostic test, so it can’t actually confirm these health conditions. Instead, the scan provides a probability that the baby might have one of these genetic disorders based on:

  • your age
  • your bloodwork
  • the result of the ultrasound

There’s a chance that the estimated due date for your baby won’t match up with when you think you conceived. There are many reasons why this might occur:

  • You may have ovulated at a different time than expected, since it’s not an exact science.
  • You might have forgotten the exact dates of your last menstrual cycle. (Don’t worry, it happens to everyone!)
  • Early ultrasounds have an error ratio of roughly 1.2 weeks when it comes to calculating estimated due dates.

If the difference between the estimated due date based on your last menstrual cycle and the one calculated by the ultrasound is more than 1.2 weeks, your doctor may request a repeat ultrasound. This will help to determine that the baby is growing as expected.

Seeing your baby for the first time can be an emotional experience, even if it’s on a screen. While this is one of many milestones in life, it’s a significant one for many.

Your first ultrasound may occur around 12 weeks. Afterward, you should know how many babies to expect, your potential due date, and whether certain genetic conditions need to be on your radar.

With this information, you and your healthcare team can have conversations about the rest of your pregnancy and any precautions they might advise. It’s important to remember to continue to receive prenatal care throughout this journey.

JPeei Clinic