Ultrasounds are one of the most effective ways for healthcare providers to monitor the health of you and your baby.
Ultrasounds can also give you exciting news about your baby’s biological sex and developmental markers.
If you’re an expecting mother, you may be wondering how many ultrasounds you need during your pregnancy.
This guide from PregnancyResource.org breaks down what an ultrasound does, what you should expect from your ultrasound appointment, and how many ultrasounds you really need during your pregnancy.
What Is an Ultrasound?
An ultrasound is a type of imaging method based on high-frequency sound waves.
Also known as a sonogram, it uses a device called a transducer to transmit soundwaves into the uterus, where they bounce off the fetus to create an image on a computer screen.
Obstetricians use a pregnancy ultrasound to check on the baby’s development and confirm their age, check for any genetic abnormalities, and examine the mother’s health.
The first image from an ultrasound is also a nice keepsake for the parents and is a staple of pregnancy announcements.
Unlike many other imaging techniques such as X-rays, an ultrasound exam does not give off any radiation. For this reason, obstetrics experts consider it safe for the mother and the baby.
Though research on the safety of ultrasounds was conducted with older equipment that emitted even less energy than today’s technology, it’s still best to only get ultrasounds as needed and are medically necessary.
While you may be excited and curious to see your baby on the ultrasound screen, it’s not recommended to schedule additional ultrasounds outside of the standard check-in timeline.
Generally, only two ultrasound scans are needed for most women — one in the first trimester and one in the second trimester.
While getting additional ultrasounds won’t pose any immediate harm, it’s best for expecting mothers to avoid spending extra time and money on ultrasound appointments unless deemed necessary by a medical professional.
What Happens During an Ultrasound?
You will be asked to lie down on a padded table during your ultrasound appointment.
An ultrasound technician or physician will apply a small amount of water-soluble gel to your abdomen, which might feel a little cold. Because this gel is water-soluble, it won’t stain your clothes.
Afterward, your doctor will place a small device called a transducer on your abdomen and slide it around.
This device sends sound waves through the skin to capture an image of your baby. The person doing the ultrasound might need up to 15 minutes to capture a full image.
A full bladder might be required prior to the ultrasound in some cases. When your OBGYN places the transducer over your bladder, you might feel some discomfort.
Otherwise, the ultrasound shouldn’t cause you to feel any uncomfortable sensations.
Other times, a transvaginal ultrasound is performed to produce enhanced image quality and to rule out certain medical conditions.
This type of ultrasound uses a special probe inserted into the vaginal canal, which may be more uncomfortable than standard pregnancy ultrasounds.
How Many Ultrasounds Do I Need?
Most women only need two scans: one first trimester ultrasound and one second trimester ultrasound.
The first ultrasound should happen between 11-14 weeks into the pregnancy. During this early ultrasound, your doctor will do the following:
- Confirm the pregnancy by checking for a heartbeat
- Establish the number of pregnancies (FYI: twins are on the rise)
- Measure the baby’s age and establish a due date
- Check for any potential complications, such as ectopic pregnancy
- Screen for genetic disorders, such as Down’s syndrome, with something called a nuchal translucency test
The second ultrasound should happen around 18-20 weeks into the pregnancy. This is the most exciting ultrasound for most expecting parents, as it can reveal the baby’s biological sex.
Of course, you can always tell your doctor not to reveal the sex so that it remains a surprise until birth — some parents may also ask the doctor to place the results in a sealed envelope so they can have the results available if they can’t bear the wait.
During this ultrasound, your gynecologist will determine your baby’s sex, in addition to:
- The baby’s growth and development
- The baby’s heartbeat and possible problems caused by heart defects
- Position of the placenta, which will determine if you need a C-section
- Early changes in the cervix, which might indicate the risk of a pre-term birth
- Umbilical cord condition
- Amount of amniotic fluid
- Anatomical abnormalities discovered during an anatomy scan, including problems with the heart, brain, or limbs
- Any other potential complications
If your doctor determines any cause for concern during these initial ultrasounds, they will ask you to come in for additional check-ups.
In the following section, we’ll go over some of the reasons you might need more than two standard ultrasounds.
Do I Need Additional Ultrasounds?
Two ultrasounds are the standard for most expecting mothers experiencing a healthy pregnancy.
Experts generally advise against non-medical-related 3D ultrasounds and 4D ultrasounds, which provide detailed “keepsake” images of the developing baby.
If your doctor detects any abnormalities during regular ultrasound screenings, additional follow-up ultrasounds may be necessary.
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Additional ultrasounds may also be necessary if your baby is at risk of birth defects. The following factors can put a baby at higher risk for complications, and might result in the need for additional ultrasounds:
- Age: Being under the age of 17 or over the age of 35 is associated with increased pregnancy complications, such as gestational diabetes or preeclampsia.
- Family history of birth defects: Birth defects run in families, so having a family history of birth defects can increase your baby’s chances of birth defects. A procedure known as amniocentesis is sometimes performed after an ultrasound to investigate any defects spotted during the scan.
- Lifestyle behaviors: Smoking, drinking, or experiencing high levels of emotional stress during pregnancy can significantly increase your chances of experiencing pregnancy complications.
- Weight: If you are underweight, there may be an increased risk of your baby being underweight at birth. Conversely, if you are overweight, then your baby’s chances of being overweight at birth increase.
- Chronic disease: Most chronic illnesses, such as asthma, high blood pressure, or diabetes are associated with an increased risk of pregnancy complications and birth defects.
- Longer gestation: Post-term pregnancies may require more ultrasounds to monitor fetal health when the pregnancy continues more than two weeks past the due date.
If you experience any of the above, you might need to see your doctor for additional ultrasounds.
The closer you get to your delivery date, the more ultrasounds you may need, and it’s not uncommon for high-risk pregnant women to have an ultrasound every week at the end of their third trimester.
Most women only need two ultrasounds: one during the first and second trimester. If your pregnancy is high-risk, then you might need more ultrasounds.
Either way, try to discuss with your doctor to make sure that you’re only getting medically necessary ultrasounds.
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Bridget Reed is a Tampa-based content development manager, writer, and editor at GR0; specializing in content related to varying fields including medicine, health, and small businesses. Bridget went to St. Petersburg College and majored in Management and Organizational Leadership.
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