Ultrasounds during pregnancy provide important medical information and help you plan your pregnancy. The American College of Gynecologists recommends that everyone get at least one ultrasound during pregnancy.
Most women get at least two ultrasounds, one in the first trimester and one in the second trimester. If your doctor has concerns about the baby’s growth or a pregnancy complication, they may order more ultrasounds in the third trimester.
Around 36 weeks of pregnancy, your provider will do a quick ultrasound in the office to make sure the baby is head down and in position for delivery.
What’s the Typical Pregnancy Ultrasound Schedule?
Most women get their first ultrasound at around 12 weeks and the second around 20 weeks in the pregnancy. But you may get an ultrasound earlier, especially if there is a concern about possible miscarriage or ectopic pregnancy. (Ectopic pregnancy is a dangerous condition when the embryo implants outside the womb).
First ultrasound: Around 12 weeks
Most women get their first ultrasound between 10 and 13 weeks of pregnancy. This ultrasound shows the number of fetuses, the fetal heartbeat, and size of the fetus(es). This helps your doctor predict your due date.
If you are 11 weeks or more along, your ultrasound technician can also perform a nuchal translucency test. This test measures the thickness of the fetus’s neck. A buildup of fluid between the spine and the skin can be a sign of Down syndrome or another genetic condition.
If you opt for a nuchal translucency test, you will also need a blood test. The health provider interprets the two tests together to determine the risk of Down syndrome and another genetic condition called Trisomy 18.
Second ultrasound: Around 20 weeks
The next ultrasound is usually performed between 18 and 22 weeks of pregnancy. This is also called the anatomy scan. In addition to looking at the baby’s organs, it also looks for any problems with the amniotic fluid or placenta.
Because baby’s organs are visible at this time, this ultrasound can reveal problems with the heart, lungs, kidneys, and other organs. This scan also shows the amount of amniotic fluid in the uterus, as high or low amounts can pose problems. The location of the placenta is also examined to make sure a vaginal delivery is safe.
The anatomy scan may not be 100% conclusive (a structure that looks abnormal in a scan may actually be normal, and vice versa). The doctor may recommend additional ultrasounds or an amniocentesis, which involves testing the baby’s DNA found in the amniotic fluid. Your doctor will discuss the risks and benefits of amniocentesis based on your age, ultrasound findings, and other factors.
For most women, however, the anatomy ultrasound reveals a healthy baby and is a reassuring milestone in the pregnancy. It is also a chance to find out the baby’s sex, for those who wish to know.
It isn’t always possible to tell the sex with certainty, due to baby’s position in the uterus. However, the technician’s assessment during this ultrasound is accurate 95% of the time.
Additional ultrasounds in the third trimester
Some clinics perform at least one routine additional ultrasound in the third trimester for all pregnancies. But many clinics only perform third-trimester ultrasounds if there’s a specific concern or if you have or develop a medical condition such as high blood pressure or diabetes.
For example, a doctor may order a third-trimester ultrasound for women who have bleeding. This could be a sign the placenta has grown close to the cervix, for example.
A common reason for a third-trimester ultrasound is a belly measurement that is lower or higher than expected. This could suggest that amniotic fluid levels are too high or too low — or the baby’s growth is slowing.
If the third-trimester ultrasound shows a potential problem with the pregnancy, the doctor can take a number of steps. They may wish to monitor the issue over time, with more ultrasounds, to see if it improves or worsens. They may also recommend an earlier birth via a planned C-section or induced vaginal delivery.
What Should I Expect During an Ultrasound?
A typical pregnancy ultrasound is around 20 minutes. But an anatomy scan at around 20 weeks can take up to 45 minutes.
For your ultrasound, you will recline back on the examining table. The technician will apply gel to the ultrasound wand and rub the wand over your belly.
The ultrasound wand sends sound waves that are not harmful to you or your baby. Based on how these sound waves bounce back from tissues, the computer generates a moving image of the baby.
Sometimes, the ultrasound technician is not able to get all views of the baby’s organs. This does not mean that there is a problem with the pregnancy but is likely due to the way the baby was positioned at the time of the ultrasound. If this happens, they can try repeating the ultrasound again in a few weeks.
The best part of the ultrasound is being able to see your future baby’s nose, fingers, and toes on the screen. The ultrasound technician can describe what you are seeing, and you are welcome to ask questions. The images from the ultrasound will be sent to your account. After the ultrasound, the doctor will explain any medical findings and next steps.