What to Expect at Your First Ultrasound

Laura Riley, M.D.
·6 min read

Getting that initial glimpse of your baby on an ultrasound machine is one of the most exciting moments of pregnancy. Yet many parents-to-be are filled with questions about the first pregnancy ultrasound: When should I get the exam? Will it hurt? What are doctors looking for? We spoke with experts to break down your most pressing questions.

What Is an Ultrasound?

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 baby's soft tissues and organs.

What Should I Expect at My First Ultrasound?

Most people will have their ultrasound done 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

This non-invasive type of ultrasound 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. Breath deeply and try to relax!

When Do You Get Your First Ultrasound?

The timing of your first pregnancy ultrasound will depend on things like your age, your medical history, your health care provider's preference, and any risks they feel you may be facing during the pregnancy.

In early pregnancy (6 to 8 weeks)

Some 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. This allows your provider to look for cardiac activity, forecast a due date, and check for multiples. It 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, M.D., 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 baby's neck (increased thickness indicates that they may be at risk for Down syndrome, trisomy 18, and other genetic disorders).

The anatomical survey (18 to 20 weeks)

By 20 weeks, most pregnant people will have already had their first ultrasound, but in rare 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, M.D., director of prenatal diagnosis at Lucile Packard Children's Hospital Stanford, in Palo Alto, California.

The baby 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.

How to Prepare for a Pregnancy Ultrasound

After you make an 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 in 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).