Finding Out Your Baby’s Gender On Ultrasound: What to Expect

If you’re pregnant, you’re likely eager to learn your baby’s sex. Many expectant parents want to know the earliest possible time they can find out. This guide will explain when you can expect to learn your baby’s sex, how accurate the results are, and how to prepare. It’s important to clarify that when we refer to gender in this guide, we are actually discussing sex, as this is how the terms are often used in medical contexts. However, it’s worth noting that sex is a biological descriptor, while gender refers to an identity, and the two are distinct concepts.

While this guide provides helpful information about prenatal ultrasounds, your doctor will officially interpret your results during a follow-up appointment or phone call. If you’d like early access to your results, PocketHealth offers secure, instant access to your report when it is available. This allows you to review the findings in advance and prepare any questions for your follow-up.

 

 

What to know about fetal ultrasounds

An ultrasound is an imaging technique that uses high-frequency sound waves to capture images of your internal structures. The sonographer uses a handheld, wand-like device called a transducer to perform the ultrasound. A conductive gel is applied to the belly, and the transducer is moved across the abdomen. As the sound waves from the transducer bounce off organs and other areas, such as your baby, images are created and stored on the sonographer’s computer for later analysis. Radiologists can then assess your baby’s size, growth, health and sex from these images.

Transvaginal ultrasounds

There are two types of prenatal ultrasounds. The first is the transvaginal method, typically used in early pregnancy when the fetus is small and better imaging angles are needed. The scan is performed by inserting a lubricated transducer into the patient’s vagina, providing clearer images due to its internal nature. After the first trimester, most patients no longer require this method and will instead have subsequent prenatal ultrasounds performed externally via the abdomen.

Transabdominal ultrasounds

Transabdominal ultrasounds are performed externally. Clear conductive gel is applied to the patient’s belly, and the transducer is moved around the abdomen to capture images of the fetus. Since the baby is larger at this stage, most of the necessary imaging can be obtained this way. For a certain period, you will likely need a full bladder for an abdominal ultrasound, as it helps improve the images. However, later in the pregnancy, this will no longer be required.

 

What is the nub theory?

Before anatomy fully develops, babies have a genital tubercle, often referred to as a ‘nub.’ The angle of this nub is thought to be a good indicator of the fetus’s sex. If the nub is parallel to the spine or less than 10 degrees from it, the theory suggests the fetus is female. If the nub is angled more than 30 degrees from the spine, the theory suggests the fetus is male. This nub can be seen as early as 11 weeks gestation, meaning you may have strong indications of your baby’s sex before your anatomy scan.

As the baby develops, the nub theory becomes more accurate. At 11 weeks, it is considered 70% accurate. By week 13, it is nearly 100% accurate. However, this is dependent on the baby being in the right position for the nub to be visible. If the ultrasound technician cannot capture the necessary images, this information will not be available. There is also a chance for inaccuracies, though these decrease as the pregnancy progresses. Because of these two factors, many patients do not learn their baby’s sex until a later ultrasound.

 

When to expect your gender ultrasound

Many patients only require two to three ultrasounds during their pregnancy. An early ultrasound, typically performed between 6 and 9 weeks gestation, is common to assess viability and confirm conception dates. However, some patients may not have this scan and it is too soon to determine gender.

The second ultrasound for many patients is a nuchal translucency screening, performed between 11 and 13 weeks gestation. This optional scan assesses the risk for genetic abnormalities and chromosomal conditions, such as Down syndrome. Some patients may get an early indication of their baby’s sex during this scan via the nub theory, but getting the right views is not always reliable.

The last common ultrasound occurs between 18 and 22 weeks gestation and is called the anatomy scan. During this appointment, the ultrasound technician evaluates the baby’s organs, structures, size and other growth markers. By this point, the baby is large enough to reliably determine the sex, which is why the anatomy ultrasound is the standard time to learn this information. That said, there may still be factors that lead to misinformation regarding fetal sex, such as inexperienced sonographers or unclear images. However, this is rare, and most gender ultrasounds have near 100% accuracy.

 

How to prepare for your gender ultrasound

If you’ve already had ultrasounds before the anatomy scan, you may have an idea of what to expect. That said, this appointment is usually longer and more in-depth than others. Here are some preparatory tips that may be useful.

Before the scan

• Go over your requisition form: If you were given ultrasound orders or other instructions, it’s helpful to review them before your appointment. This way, you won’t inadvertently miss any preparatory instructions, such as having a full bladder for your appointment.
• Ask if you can bring someone with you: Most imaging facilities allow patients to bring a support person, especially for the momentous gender ultrasound. However, there may be limits on how many people can attend, as well as policies regarding small children.
• Ask if the technician is allowed to tell you the sex: If you’re eager to know your baby’s sex, it’s a good idea to ask in advance whether this information will be shared during your appointment. Legally, ultrasound technicians are not supposed to provide medical details during the appointment, and some clinics strictly adhere to this policy, including withholding information about the baby’s sex. However, many sonographers are permitted to give this specific information. It depends on the clinic’s policies.

The day of the scan

• Arrive with a full bladder: Most anatomy ultrasounds require a full bladder to improve imaging, as sound waves move best through liquid. Occasionally, there may be exceptions to this preparation.
• Dress in comfortable clothes: Since your anatomy scan is typically external, you may not need to change into a hospital gown. Wearing clothes that easily expose your belly can make access easier for the ultrasound technician.
• Bring your requisition form: This is helpful if the imaging clinic hasn’t already received your ultrasound orders, as it saves time. Also, bring your health card and ID.
• Inform your sonographer if you don’t want to know the sex: If the technician is permitted to give you this information, some patients prefer not to know or to be surprised at a later date. Some even ask the sonographer to write the sex in an envelope so they can read it at a gender reveal party or later with loved ones. If this is your preference, let the technician know before the scan begins.

 

Getting your results

After your appointment, the radiologist will review your ultrasound images to create a final report and findings. This information will then be sent to your obstetrician, who will discuss it with you at your follow-up appointment or via a phone call. Since some patients may not have the baby’s sex revealed during the ultrasound, it’s understandable that many are eager to find out this information.

How quickly will you get your prenatal report and ultrasound pictures?

Many imaging clinics will give you a few ultrasound printouts at your appointment, though this can vary by facility. How quickly you receive your results will depend on the schedule of the radiologist and your obstetrician. Many patients will get their final anatomy report at their follow-up visit.

If you’d like to view your report before your appointment, PocketHealth provides faster access, allowing you to see the results as soon as they are officially uploaded. This gives you time to review the findings and prepare for your next medical visit. MyCare Navigator is especially helpful for offering personalized insights and identifying any recommended follow-up steps. It helps you formulate specific, relevant questions to ask your doctor, ensuring you make the most of your consultation.

Understanding my report

Although your doctor will provide an official explanation of your results, accessing your report before your appointment can give you an early glimpse. It’s common to find the medical terminology complex and confusing, but PocketHealth Report Reader makes it easier by offering clear, straightforward definitions for medical terms—simply tap or click on any underlined words to reveal their meaning.

Note, if you don’t want to know the sex of your baby yet, be aware that it may appear in your final report. However, if you receive your ultrasound report before your doctor reviews it with you and want a better understanding, here are some helpful terms to know regarding the baby’s sex:

• Dome sign: If the ultrasound technician observes a dome shape between the fetus’s legs, it often suggests the presence of a scrotum and penis, indicating a male.
• Three lines: Also known as the “hamburger sign,” this can suggest a female fetus. The three lines represent the labia minora, labia majora and the clitoris.
• Genital tubercle pointing up: According to the nub theory, this typically indicates a male fetus.
• Genital tubercle horizontal/down: According to the nub theory, this typically indicates a female fetus.
• Fetal sex has been determined: This phrase is often followed by the sex of the baby. If you’re trying to avoid learning this information, it’s a good cue to stop reading.

 

 

Frequently asked questions

Since this is a topic many expectant parents find exciting, here are some common questions about how to find out the baby’s sex.

How accurate are ultrasounds for determining the baby’s sex?

The accuracy of ultrasounds for revealing gender depends on the baby’s gestational age, the angle of the baby and the skill of the sonographer. Another important factor for determining gender is if there are multiple fetuses. It’s not uncommon for one twin to block the view of the other, making it more challenging to get clear images. Overall, however, typical accuracy tends to be:

• 11 weeks: Up to 70%
• 12 weeks: Up to 98%
• 13 weeks: Up to 99%
• 18-22 weeks: 99%

While it may seem that patients can learn their baby’s sex with nearly perfect accuracy by 12 weeks, it’s common for the baby to be positioned at the wrong angle, making this determination difficult. The information is reliant on very specific views, so patients often don’t learn the sex during earlier ultrasounds.

What is gender DNA testing?

Another method for determining the baby’s sex, aside from an ultrasound, is gender DNA testing. While everyone’s blood contains their own DNA, a pregnant person’s blood also contains DNA from the fetus. A blood sample is taken from the patient, and if male chromosomes are detected, it can indicate a male fetus. If no male chromosomes are found, it suggests a female fetus.

This test can be done as early as six weeks. There are several gender DNA testing products available, many of which can be done at home, though they can be expensive and insurance often doesn’t cover them. Most of these companies claim near 99% accuracy, even at 6 weeks, but there are important factors that may affect this assertion:

• If gestational dating is off: If the patient hasn’t confirmed they are at least six weeks gestation via an ultrasound, they may take the test too soon and get a false result indicating a female fetus, as male chromosomes may not be detectable yet.
• Sample contamination: If the blood sample is contaminated during transit or handling, it could result in a false positive, suggesting a male fetus. For instance, if male DNA, such as skin cells, contaminates the sample, it could affect the results. For this reason, some patients prefer to have their blood sample taken at a lab rather than at home, where contamination may be harder to control.

Does amniocentesis and chorionic villus sampling reveal gender?

Both of these tests can help assess the risk of chromosomal conditions, similar to a nuchal translucency test. If you undergo these prenatal tests, they may also provide an early indication of your baby’s gender. Here’s a quick overview:

• CVS (chorionic villus sampling): This test involves collecting a sample of the placenta to check for chromosomal abnormalities. It is typically performed between weeks 11 and 13 and is considered 99% accurate for determining fetal sex.
• Amniocentesis: This procedure involves collecting and testing a sample of amniotic fluid. It is also considered 99% accurate for predicting gender.

What’s the earliest you can find out the baby’s gender?

If you choose the gender DNA test route, you could theoretically find out as early as six weeks, though it’s not a foolproof method. With an ultrasound, you might find out at 11 weeks, provided the fetus is in the right position to use the nub theory. CVS testing at 11 weeks is considered quite accurate and doesn’t require specific imaging to determine the gender, making it easier to obtain. Otherwise, many patients learn their baby’s sex at the 18-22 week anatomy scan.

What happens if they can’t tell the gender of the baby at the anatomy scan?

Occasionally, even at the anatomy scan, the baby may be in the wrong position. If the baby is turned away or has an arm or leg obstructing the view, the sex may not be discernible. If there are no medical restrictions, drinking something sweet 30 minutes before your appointment can help make the baby more active, improving the chances of getting good images. The technician may also have you adjust your position to see if that encourages the baby to move. If they still can’t get the right angle, it’s common to schedule a follow-up appointment to try again.

 

Feel confident throughout your pregnancy journey

PocketHealth makes it simple to keep track of your prenatal reports and ultrasounds. All of your vital imaging is in one secure location and can be accessed online anytime. If needed, reports can also be easily shared with other physicians in your care team. When used in conjunction with your medical provider’s professional advice, it is a powerful tool for organizing and understanding your imaging results and pregnancy health. With such easy access to all of your ultrasounds, you can also print them from home or even share them with friends and family.