12 Week Ultrasound: What Findings to Expect & How to Prepare

During the 12-week first-trimester ultrasound scan, the following happens in a typical span of 20-30 minutes:

1. You’ll be ushered into a dimly lit room by a sonographer or your pregnancy doctor.
2. The sonographer asks you to lie on an examination table on your back and reveal your tummy for an abdominal ultrasound.
3. The sonographer puts an ultrasound gel on your tummy to help transmit the ultrasound waves between the probe and your skin. 
4. The sonographer will pass the probe over your tummy to produce a picture of your baby on the ultrasound machine screen.
5. The sonographer examines your baby’s structure and organs. That may mean applying a bit more pressure, once in a while, to get the best images.
6. The sonographer takes measurements of the baby’s organs, like the head and trunk, and captures the best real-time images of your baby. You will also see and hear your baby’s heartbeat.
7. The sonographer makes printouts of your baby’s images and shares them with you.
8. The sonographer wipes the gel and asks you to rise from the examination table. And, with that, the ultrasound is complete.

If your baby is lying in a position that makes clear imaging difficult, the scan may take more than 30 minutes, or the doctor may recommend a transvaginal ultrasound instead.

You can learn the following from a 12 week pregnancy scan:

• The gestational age and the estimated date of birth.
• If you are expecting one baby, twins, or triplets.
• If your unborn baby’s heartbeat is within the normal 110-160 beats per minute.
• The growth status of your baby’s organs and limb formation.
• If the placenta location and amniotic fluid levels are within the norm.
• If there are any signs of chromosomal abnormalities, such as additional fluid at the back of the fetus’s neck, for Down syndrome.
• If your baby’s overall growth and development are as expected.

You will notice:

• The outline of a well-formed fetus, the size of a plum (about 2 inches/4.5cm), with clear head and body structure.
• The tiny legs and arms with fingernails and toenails just beginning to form.
• The umbilical cord that gradually moves into the fetus’s abdomen as the wall closes.
• The dark space around the fetus that is filled with amniotic fluid.

👉 For an extended, step-by-step guide on how to read a pregnancy ultrasound, check our complete guide on how to read an ultrasound.

A normal 12-week ultrasound scan shows a normally developing baby with:

An abnormal 12-week ultrasound will show:

Most 12-week ultrasound scans are normal and reassuring. A few show abnormalities. Research suggests that fetal abnormalities detected in fetuses during the 12-week scan range from 0% to around 1%.

Here are a few examples:

• A 2019 study with >100,000 pregnancies: 1.7% had fetal abnormalities.
• A 2004 study with 1609 fetuses: 14 (0.009%) showed structural abnormalities. 
• Data by the Harris Birthright Research Center for Fetal Medicine: 1% of fetal ultrasounds show abnormalities.

Yes. A 12-week scan can detect miscarriage, specifically a missed or delayed miscarriage, through the following signs:

• Detection of an empty pregnancy sac.
• Absence of fetal heartbeat.
• Retarded development (too small for the pregnancy age).

Preparation for a 12 week ultrasound scan is simple:

• Drink 2-3 glasses of water an hour before the ultrasound, as a 12-week ultrasound is clearer if you have a full bladder. 
• Wear loose clothing that is comfortable enough to allow you to reveal your belly easily. 
• Bring a support person along if you need to. It’s always better to be accompanied.
• Keep in mind any questions you may want to ask your doctor.

Yes. While it is more difficult than with the second-trimester anomaly or anatomy scan, the 12-week dating scan can determine your baby’s gender. But that depends on factors such as the sonographer’s skills and the quality of the ultrasound machine.

A study reported a 91% accuracy in gender detection at the 11th and 12th weeks of pregnancy using ultrasound imaging, with greater accuracy observed for female fetuses.

Yes. It is possible, but rare, for a dating scan to miss twins. It mostly happens if one fetus is blocked from the sonographer’s view by the other, especially with the rare monochorionic twins (identical twins that share an amniotic sac).

Taking a dating ultrasound at 12 weeks of pregnancy is an exciting moment for parents. You get to see your baby for the first time. 

Your sonographer or doctor will tell you the date of birth of your baby from a 12 week ultrasound scan. You also get to find out if your baby is developing as expected, and if you are lucky, whether it’s a girl or a boy!

Ask your doctor any questions you might have during a 12 week pregnancy scan. That way, you can enjoy your pregnancy with greater peace of mind.

• ACOG: Ultrasound Exams.
• Cleveland Clinic: Ultrasound in Pregnancy.
• UPMC: What Is the Typical Pregnancy Ultrasound Schedule?
• NHS: Ultrasounds in Pregnancy.
• NIH: How do health care providers diagnose Down syndrome?
• Syngelaki, A. (2019). Diagnosis of fetal non-chromosomal abnormalities on routine ultrasound examination at 11–13weeks’ gestation. Ultrasound Obstet. Gynecol., 54, 468–476. 
•  Chen M, Lam YH, Lee CP, Tang MH. (2004). Ultrasound screening of fetal structural abnormalities at 12 to 14 weeks in Hong Kong. Prenat. Diagn., 24(2), 92-97. 
• Harris Birthright Research Center for Fetal Medicine: The 11-14 Week Scan.
• Gharekhanloo F. (2018). The ultrasound identification of fetal gender at the gestational age of 11-12 weeks. J Family Med Prim Care, 7(1), 210-212.