What To Expect at Your First Ultrasound During Pregnancy

That first ultrasound during pregnancy can cause various emotions. No matter what you're feeling, you can typically expect it sometime in the first trimester. A first ultrasound can confirm pregnancy, help determine the fetus' gestational age, and estimate a due date. But for others, the first pregnancy ultrasound is the anatomy scan, which is performed around 20 weeks.

Many parents-to-be are understandably filled with questions about their first pregnancy ultrasound. For starters, an ultrasound is a painless diagnostic test that most people receive at least once during routine prenatal care. High-frequency sound waves travel into the uterus, then bounce back off the embryo or fetus as vibrations. The echoes are translated into electrical signals that are projected as black-and-white pictures on a monitor. The images display the fetus's soft tissues and organs. A pregnancy ultrasound is considered a safe procedure for you and the fetus.

You may also be wondering when you should get your first ultrasound, how it will feel, and what providers are looking for. Experts break down your most pressing questions.

When Should You Get Your First Ultrasound?

The timing of your first pregnancy ultrasound will depend on things like your age, your medical history, your cycle regularity and last menstrual period (LMP), your health care provider's preference, and any risks they feel you may be facing during the pregnancy. For many people, a first ultrasound is performed at around 8 weeks. But it may also be performed later on.

An early scan (6 to 8 weeks)

Many providers schedule their patients' first ultrasound around 6 to 8 weeks into the pregnancy, which could be during the first prenatal visit. Others will only arrange for an ultrasound that early if the pregnancy is considered high-risk, whether because of age, current medical symptoms (bleeding, abdominal pain), or a history of miscarriage, congenital abnormalities, or pregnancy complications.

At this time, the embryo is tiny, and your uterus and fallopian tubes would be closer to your birth canal than to your abdomen, so a transvaginal ultrasound is clearest. Your provider will typically look for cardiac activity, forecast a due date, check for multiples, and viability. An ultrasound at this time can also be used to screen for an ectopic pregnancy, a rare condition in which the fetus grows in the fallopian tube instead of the uterus.

The dating ultrasound (10 to 13 weeks)

Ultrasounds conducted around 10 weeks capture the baby's growth. The ultrasound technician will measure the length of their body from crown to rump, which serves as a marker of gestational age (and better predicts a due date).

"This helps us determine if the size of the fetus matches up with the size it should be based on the patient's last menstrual period," says Michele Hakakha, MD, an OB-GYN in Beverly Hills and the co-author of Expecting 411. "A smaller crown-rump length may signal an embryo that is not developing normally and may have a chromosomal problem." It could also mean your estimated due date based on your last menstrual period was off, which is common for people with irregular cycles.

During this period, you may be offered a nuchal translucency (NT) test, which evaluates your child's risk of chromosomal abnormalities and certain congenital heart disorders. This two-part exam includes a blood test that measures the level of specific hormones and proteins in your body and an ultrasound that assesses thickness at the back of the baby's neck (increased thickness indicates that they may be at risk for Down syndrome, trisomy 18, and other genetic disorders). The NT ultrasound is a personal choice. It’s always best to discuss the pros and cons with your health care provider.

The anatomical survey (18 to 20 weeks)

By 20 weeks, most pregnant people will have already had their first ultrasound, but in some cases, the 20-week ultrasound, also known as the anatomy scan, is the first. This routine ultrasound is fairly comprehensive. "We look at about 35 elements, including the brain, heart, kidneys, limbs, face, sex, and more," says Jane Chueh, MD, director of prenatal diagnosis at Lucile Packard Children's Hospital Stanford in Palo Alto, California.

The fetus will have measurements taken of the diameter and circumference of their head, the circumference of their abdomen, and the length of their femur bone. Ultrasounds can't detect all medical and genetic issues, but they can highlight physical characteristics that are suggestive of potential disorders.

Additional ultrasounds

There are instances where a person may need extra ultrasounds, such as if there are issues with the cervix, amniotic fluid, or the placenta location or size. You may also need growth ultrasounds to ensure the fetus is staying on its growth curve if you are a pregnant person with diabetes, preeclampsia, hypertension, or placenta or uterus issues.

What Should I Expect at My First Ultrasound?

Most people will have their first ultrasound in their prenatal care provider's office or a local hospital, though there are also freestanding facilities that offer them. There are two types of pelvic ultrasounds that a pregnant person can have: a transvaginal ultrasound or a transabdominal ultrasound. Which method is used will depend on how far along the pregnancy is.

Transvaginal ultrasound

Given early in pregnancy, transvaginal ultrasounds use a wand-shaped probe (a transducer covered with a latex sheath and lubricant) that is inserted inside the vagina. It offers a very detailed look at the embryo and helps health care providers assess how far along a pregnancy is. To get a good picture, the ultrasound technician may move the device, but any discomfort should be minimal.

At this point, the embryo is very small and located deep in the pregnant person's pelvis; since sound waves can't pass through bones, a technician may approach the uterus through the cervix. This exam may also be used later in pregnancy if the person expecting develops placenta previa (a condition in which the placenta covers the cervical opening) or the provider needs to measure the cervix itself.

Transabdominal ultrasound

A transabdominal ultrasound is a non-invasive type of ultrasound that tends to be more common after 11 to 12 weeks of pregnancy. The technician moves the transducer along a pregnant person's abdomen, applying a small amount of pressure as they go. The transducer transmits sound waves that create a picture of the fetus inside the body, and it may be rotated at different angles to get a complete picture. If you're ticklish, you might find yourself challenged by this procedure. Breathe deeply and try to relax!

What Your Provider Is Looking for at Your First Ultrasound

Early ultrasounds are typically looking for the following:

• Pregnancy viability 
• Heartbeat
• Number of fetuses
• Size of the fetus
• Due date confirmation

How To Prepare for a Pregnancy Ultrasound

After you make an ultrasound appointment, your health care provider may give you an instruction sheet telling you what to do next. People who are less than 14 weeks pregnant are usually asked to fill their bladders to capacity before the exam. Sound waves travel better through liquid, and a full bladder improves the quality of the ultrasound. As the pregnancy progresses, this is not as essential because the uterus and fetus become so large—but even then, some providers still ask patients to come to the ultrasound appointment with bladders full.

Otherwise, if you'll be having an abdominal rather than a transvaginal ultrasound, you might consider wearing a two-piece outfit that provides easy access to your tummy—and one that you won't mind getting a little ultrasound gel on (Don't worry: It'll come out in the wash).