Start Here: Your Complete Ultrasound Roadmap

Growth, EFW & EDD: What Your Sonographer Wants You to Know

You may walk into a growth ultrasound expecting to find out how much your baby weighs, but once you’re on the ultrasound table, other questions may come up:

Is my baby growing okay?

Is the baby too small or too big?

Did the due date change?

What if the baby isn’t measuring as expected?

If you’ve heard terms like EFW, growth percentile, or EDD, you may have left wondering what they mean.

As a sonographer, I hear these questions often. And I want you to know:

The numbers on the screen don’t tell the whole story.

First, What Is a Growth Ultrasound?

A growth ultrasound assesses your baby’s growth and development.

Your provider may order one for routine follow-up, to monitor a possible growth concern, during a high-risk pregnancy, or to follow your baby’s development over time.

During the examination, I may:

• Measure different parts of your baby’s body
• Assess amniotic fluid
• Examine the placenta
• Evaluate fetal position
• Obtain additional images based on your provider’s orders

There will be numbers—a lot of them.

But they aren’t there to scare you. They provide information your healthcare team uses to understand how your baby is growing.

EFW: Estimated Fetal Weight

EFW stands for Estimated Fetal Weight.

The important word is estimated.

Ultrasound doesn’t place your baby on a scale. Instead, measurements of different fetal body parts are entered into an established calculation to estimate weight.

For example, you may see:

EFW: 1,850 grams

That does not mean your baby was weighed directly. The number is based on ultrasound measurements and may have a margin of error.

So try not to let one number become the entire story.

Your provider considers EFW alongside the rest of the examination and your clinical history.

What Measurements Are Used?

During a growth ultrasound, you may hear terms such as:

BPD — Biparietal Diameter
A measurement across your baby’s head.

HC — Head Circumference
A measurement around your baby’s head.

AC — Abdominal Circumference
A measurement around your baby’s abdomen.

FL — Femur Length
A measurement of your baby’s thigh bone.

Together, these measurements help assess growth and calculate EFW.

Why Don’t All the Measurements Match?

You may notice that one measurement corresponds to a slightly different gestational age than another.

That can be confusing.

You may wonder:

“Why aren’t they all exactly the same?”

Babies don’t grow like perfectly measured charts. Measurements can vary, and your baby’s position may make certain images more difficult to obtain.

Ultrasound measurements also have limitations.

That’s why your healthcare team looks at the overall pattern, rather than interpreting one number in isolation.

Understanding Growth Percentiles

You may hear:

“Your baby is measuring in the 45th percentile.”

And immediately wonder:

“Is that bad?”

A percentile compares your baby’s estimated size with that of other pregnancies at the same gestational age.

It is not a grade.

It does not mean your baby is “passing” or “failing.”

Your provider interprets the percentile alongside:

• Your pregnancy history
• Your baby’s measurements over time
• Other findings from the examination
• Any relevant medical concerns

If you’re unsure what the percentile means, ask:

“Can you explain this number in the context of my individual pregnancy?”

You deserve to understand the information you’re given.

EDD: Estimated Due Date

EDD means Estimated Due Date.

A due date is an estimate used to establish the timing of your pregnancy and guide your prenatal care. It is not necessarily the exact day your baby will arrive.

Your due date may be established early in pregnancy. Depending on your circumstances and your provider’s assessment, it may or may not change based on later ultrasound measurements.

A baby measuring slightly ahead or behind during a later growth scan does not automatically mean your due date should change.

Growth and dating are not the same thing.

Your baby can measure larger or smaller than average without changing how far along your pregnancy is.

From the Sonographer’s Side of the Screen

While you’re watching the screen, I’m checking images, documenting findings, and working to obtain the views needed for the examination.

I may:

• Repeat a measurement
• Adjust the transducer
• Ask you to change positions
• Wait for your baby to move
• Try a different angle

Sometimes I may become quiet.

You may immediately think:

“They’re seeing something wrong.”

But silence doesn’t automatically mean bad news.

I may simply be concentrating, trying to obtain a specific image, or working around your baby’s position.

My concentration isn’t a diagnosis.

And my facial expression isn’t your ultrasound report.

When the Numbers Don’t Match Your Expectations

Maybe you were told your baby is measuring small.

Maybe you were told your baby is measuring large.

Maybe the EFW or percentile surprised you.

It’s understandable to feel worried.

Ultrasound is a powerful tool, but it isn’t a crystal ball. Measurements are estimates, images have limitations, and babies don’t always follow a textbook growth pattern.

Your provider considers the complete clinical picture when deciding whether additional monitoring, testing, or follow-up is needed.

If you leave with questions:

1. Write them down.
2. Ask your provider to explain them.
3. Avoid Googling yourself into panic.
4. Try not to assume one number tells you everything about your baby’s health.

What I Want You to Remember

You may find yourself trying to decode every number on the screen.

But you don’t have to interpret the examination yourself.

My role is to perform the examination and obtain the appropriate images and measurements.

Your provider interprets the findings in the context of your overall care and discusses what they mean for you.

Your job?

Ask questions.

You can say:

“Can you explain what EFW means?”

“What does the percentile mean?”

“Is the growth being followed over time?”

“Has my estimated due date changed?”

“When will my provider review these results with me?”

These are reasonable questions.

You are not being difficult.

You are participating in your healthcare.

The Baby Behind the Numbers

At the end of the examination, you may leave with a page full of measurements:

• BPD
• HC
• AC
• FL
• EFW
• Percentile
• EDD

It can feel like a lot, but behind every number is a developing little person you’ve probably already imagined holding, and behind every appointment is a parent who may be excited, nervous, or carrying fears from a previous experience.

I see the measurements, but I also see you.

A Little Reassurance From Your Sonographer

If you’re waiting for your growth ultrasound and feeling anxious, take a breath. You don’t have to understand every number before you leave. You don’t have to interpret the screen yourself. And you don’t have to pretend you’re not nervous.

Tell your sonographer or provider. Ask questions. Let yourself be informed without allowing one number to steal your peace before you understand what it means.

Sometimes the hardest part of an ultrasound isn’t what appears on the screen.

It’s everything your mind imagines before someone explains it.

That is the gap First Hello was created to bridge.

From image to understanding.
From numbers to context.
From uncertainty to informed care.

Welcome to First Hello. 🤍

First Hello provides educational information and does not replace individualized medical advice, diagnosis, or treatment from your healthcare provider. EFW is an ultrasound-based estimate, not a direct measurement of fetal weight. Interpretation of fetal growth, percentiles, and EDD should be individualized by your healthcare provider based on the complete clinical picture.

The Anatomy Scan: More Than Just Finding Out What Your Baby Looks Like

The anatomy scan can be one of the most anticipated ultrasounds of pregnancy.

You may have been counting down to it for weeks. Maybe you’re excited to see your baby again. Maybe you’re hoping for a beautiful profile picture. Maybe you’re excited to find out, or confirm your baby’s sex, but underneath all of that excitement, there may be another feeling that you don’t talk about as much:

Fear.

Because you know this ultrasound is looking at more than a cute picture. You know the sonographer is looking at your baby’s anatomy. And suddenly, every movement of the transducer feels important. You may find yourself watching the screen. Watching the sonographer. Listening to every word.

And wondering:

“Does everything look okay?”

As a sonographer, I understand that because while you’re experiencing this appointment as a parent, I’m experiencing it as a healthcare professional who knows just how meaningful this moment is to you.

From the Sonographer’s Side of the Screen

When I begin an anatomy scan, I’m not simply looking for a beautiful picture. I’m working through a detailed examination of your baby’s anatomy. Depending on your gestational age, the reason for the examination, and your provider’s orders, I may be evaluating structures such as:

• Your baby’s brain and head
• The face and facial profile
• The spine
• The heart and its structures
• The chest and lungs
• The stomach
• The kidneys and bladder
• The abdominal wall
• The arms, legs, hands, and feet
• The umbilical cord and its vessels
• The placenta
• The amniotic fluid
• Cervical and maternal structures as indicated

There are measurements to take. Images to document. Structures to identifyViews to obtain, and sometimes, there are images that require patience because your baby simply isn’t cooperating. But while I’m focused on all of that, I know you’re lying there thinking about something completely different.

Your baby.

While I’m Measuring, You’re Watching

You may notice that I’m moving the transducer around. I may pause. I may measure something. Then measure it again. I may zoom in. I may change angles. I may ask you to turn on your side. I may ask you to walk around. I may even tell you that I need to try again because your baby’s position isn’t giving me the view I need. And I know what you might be thinking:

“Why are they taking so long?”

“Did they see something?”

“Why aren’t they saying anything?”

Sometimes, the answer is simply:

Your baby is being a baby.

They may have their back turned. Their face may be tucked away. Their hands may be covering their face. Their legs may be crossed. Their position may make a particular image difficult to obtain. That doesn’t automatically mean something is wrong. Sometimes it just means we need a little more patience.

The Quiet Moments

There may be moments when I become very quiet. And I know how quickly your mind can fill that silence. You may look at my face. You may look at the screen. You may wonder if I’m seeing something you can’t see. But my silence doesn’t automatically mean something is wrong.

I may be concentrating. I may be trying to obtain a specific cardiac view. I may be measuring a structure. I may be documenting an image. I may simply be working through the examination carefully.

My quiet is not a diagnosis.

And my facial expression isn’t your ultrasound report. I wish every patient knew that before they walked into the room.

The Heart

For many parents, the heart can be one of the most emotional parts of the anatomy scan. The fetal heart is small(about the size of an acorn). The examination requires specific views. And obtaining those views can take time. You may hear the sonographer say things like:

“I need one more view.”

Or:

“I’m going to try to get a different angle.”

You may immediately wonder why, but often, we’re simply working to obtain the images needed for the examination. You may be staring at the screen seeing what looks like a tiny flicker. I’m looking at anatomy, motion, and specific structures. We’re seeing the same image, but we’re seeing it through two very different experiences.

When We Can’t Get Every Picture

This is something I especially want parents to understand. Sometimes we simply can’t get every image during one appointment. Maybe your baby won’t turn. Maybe the baby’s position makes part of the anatomy difficult to visualize. Maybe your body position or other technical factors make certain views challenging.

Sometimes the recommendation is simply:

“We need to come back and get a few more images.”

I know those words can make your heart drop.

You may immediately think:

“They found something wrong.”

But an incomplete examination does not automatically mean an abnormal finding. Sometimes we simply need another opportunity to see what we couldn’t see clearly the first time. And sometimes your provider may recommend additional imaging for reasons specific to your pregnancy. The important thing is to ask what the follow-up is for rather than allowing your mind to fill in the blanks.

The Moment You See Your Baby’s Face

And then there are the moments that have nothing to do with measurements.

Your baby’s face comes into view. Maybe you see the profile. A little nose. A mouth.A hand near the face. Tiny feet. A stretch. A yawn-like movement.

And suddenly, the clinical examination becomes incredibly personal. You may laugh. You may cry. You may call your partner over. You may stare at the screen completely speechless. I’ve seen those reactions, and even after performing countless ultrasounds, I don’t forget what that moment means to the person lying on the table because for me, I’m doing my job. For you, you’re meeting your baby in a completely different way.

I Know You’re Looking at My Face

During an anatomy scan, you may spend as much time watching me as you do your baby. You may be trying to read my expression. You may wonder if I’m smiling because something looks good. You may wonder if I’m quiet because something looks concerning. You may wonder why I typed something into the computer. I understand why. You’re looking for reassurance wherever you can find it,but I want you to remember:

You cannot diagnose your pregnancy by studying your sonographer’s face.

My role is to perform the examination, obtain the appropriate images and measurements within my scope, and document what I see.

The findings are then interpreted according to your healthcare team’s process, and your provider can discuss the results and what they mean for you.

If You’re Anxious, Tell Me

You don’t have to walk into your anatomy scan pretending you’re calm.

You can tell your sonographer:

“I’m really nervous about this scan.”

“I’ve been thinking about this appointment for weeks.”

“I’ve had a previous loss.”

“I’m scared something will be wrong.”

“Can you tell me what you’re doing as you go?”

You may not receive every answer from the sonographer, because there are professional boundaries around interpretation and diagnosis, but your emotions still matter.

Your sonographer can know that you’re nervous. Your provider can answer the questions that fall within their role, and you can advocate for yourself throughout the process.

The Anatomy Scan Is More Than a Checklist

By the end of the appointment, I may have collected dozens of images and measurements. To me, they are part of a detailed examination. To you, they represent something much bigger. They’re your baby’s heart. Your baby’s brain. Your baby’s tiny hands and feet. Your baby’s developing body. They’re pieces of a little person you’ve already started loving, and that’s something I never want to lose sight of.

Behind every image is a person waiting for answers.

Behind every measurement is a parent hoping everything is okay. Behind every ultrasound screen is a human being experiencing a moment they’ll remember.

If You’re Lying on That Table Right Now

Take a breath. You don’t have to understand every image. You don’t have to know what every measurement means. You don’t have to interpret the silence, and you don’t have to assume that every time the sonographer pauses, something is wrong. Let the examination happen. Ask questions when appropriate. Write down anything you want to discuss with your provider, and remember that sometimes the anatomy scan takes time because we are being thorough.

Your baby may wiggle.

Your baby may hide.

Your baby may refuse to give us the perfect picture.

That’s okay.

Sometimes the little one on the screen already has their own plans.

From One Sonographer to the Parent on the Table

I’ve been on the other side of the screen enough times to understand that an ultrasound is never just an ultrasound to the person experiencing it. It’s anticipation. It’s hope. It’s fear. It’s curiosity. It’s love. Sometimes it’s healing. Sometimes it’s the first time you’ve allowed yourself to believe that this pregnancy is really happening, and sometimes, especially after loss, getting excited can feel terrifying.

Whatever you’re feeling when you walk into that room, you don’t have to apologize for it.

You are human. You’re carrying more than a pregnancy. You’re carrying hopes, dreams, questions, and sometimes fears that nobody else in the room can see, and while I’m looking at your baby’s anatomy, I know there’s something else sitting quietly in that room too: your heart.

That’s the part of ultrasound I never want patients to feel is invisible.

I see the anatomy.
I see the measurements.
But I see you, too.

And that is the heart of First Hello.

Where ultrasound meets understanding. 🤍

First Hello provides educational information and does not replace individualized medical advice, diagnosis, or treatment from your healthcare provider. The anatomy scan is a detailed ultrasound examination, but the exact components and findings assessed can vary based on gestational age, clinical indication, provider orders, and the imaging performed. A sonographer’s role is to perform and document the examination within their scope; your qualified healthcare provider interprets the findings and discusses results and next steps with you.

The Biophysical Profile: When an Ultrasound Feels Like More Than an Ultrasound

A biophysical profile, or BPP, is a prenatal test that uses ultrasound—and sometimes fetal heart rate monitoring—to assess several signs of fetal well-being, including movement, breathing movements, muscle tone, and amniotic fluid.

Unlike an earlier pregnancy ultrasound focused primarily on anatomy and development, a BPP is often ordered when your healthcare provider wants to monitor your baby more closely. That can make the appointment feel emotionally significant. You may be watching for movement, wondering why the test was recommended, or waiting anxiously to hear what the findings mean.

Maybe you’re familiar with the ultrasound room by now. You know the machine, the table, and the routine.

But this appointment may carry a little more weight.

You may find yourself wondering:

“Why do I need this test?”
“Is my baby okay?”
“What are they looking for?”

As a sonographer, I understand how quickly an appointment can feel overwhelming when you don’t fully understanding why you’re being monitored.

So let’s talk about what a BPP actually looks like from the other side of the screen.

What Is a Biophysical Profile?

A biophysical profile is a prenatal assessment that uses ultrasound and, depending on the testing protocol, fetal heart rate monitoring to evaluate certain signs of fetal well-being.

During the ultrasound portion, I may assess:

• Fetal movement
• Fetal breathing movements
• Fetal muscle tone
• Amniotic fluid
• Other observations or measurements according to your provider’s orders

The goal isn’t simply to get a picture of your baby. I’m looking for and documenting specific findings during the examination.

You’re Watching the Baby. I’m Watching for Specific Things.

You may see your baby stretch and think:

“Look at that!”

I may be documenting that movement as part of the examination. You may see what looks like a little breathing motion. I’m watching for specific fetal breathing movements. You’re experiencing your baby. I’m performing an examination.

We’re looking at the same screen, but from two very different perspectives.

Sometimes Baby Doesn’t Cooperate

Your baby may be sleeping. They may be tucked into a position that makes certain movements difficult to observe. They may simply decide that today is a good day to be still. I may continue scanning, adjust the transducer, change angles, or ask you to change positions depending on the circumstances and protocol.

Sometimes we simply need patience.

A quiet baby during part of an examination does not automatically mean something is wrong.

The examination is designed to assess specific findings over time, and your healthcare team interprets those findings in the context of your pregnancy.

The Quiet Moments

During a BPP, I may become very focused. I’m watching, measuring, documenting, and waiting for specific things. You may be watching my face or wondering why the examination is taking longer than expected.

But remember:

My concentration is not a diagnosis.

My silence isn’t automatically bad news, and my facial expression isn’t your test result. My role is to perform and document the examination within my scope. Your healthcare provider interprets the findings and discusses what they mean for you.

When You’re Waiting for Baby to Move

This can be one of the more emotional parts of a BPP. You may find yourself willing your baby to move.

“Come on, baby.”

Then they finally stretch, roll, or move and you breathe a little easier.

I understand that moment. For you, it’s your baby. For me, that movement is also part of the examination.

That intersection between clinical information and human emotion is something I never want to lose sight of.

What About the Amniotic Fluid?

Another component of the BPP may be an assessment of the amniotic fluid. You may see me measuring pockets of fluid and notice numbers appearing on the screen. It can be tempting to immediately wonder:

“Is that number okay?”

Try not to let one measurement become the entire story. Your provider considers the BPP findings alongside your pregnancy history, other testing, symptoms, and the overall clinical picture.

Ultrasound provides information. Your healthcare provider puts that information into context.

Why Am I Being Monitored More Closely?

If your provider has ordered a BPP, you may already feel like your pregnancy is being watched more closely than you expected. That can be stressful. There are many reasons a provider may recommend additional fetal surveillance, and those reasons are specific to the individual pregnancy. If you aren’t sure why you’re having a BPP, ask:

“Can you explain why this test was ordered for me?”

“What are you monitoring?”

“What happens after the results are available?”

Those are completely reasonable questions.

When the Scan Takes Longer Than Expected

You may think:

“Why is this taking so long?”

Sometimes we’re simply being thorough.

We may need more time to observe fetal activity, obtain specific images, or document a finding clearly. Your baby’s position can also make certain observations more difficult.

From your side of the screen, extra time can feel concerning. From mine, it may simply mean:

I’m doing the examination carefully.

When the Examination Is Over

Once the ultrasound portion is complete, you may still be thinking about everything that happened in the room. How much your baby moved. How long the examination took. What numbers you saw. How quiet I was. It’s natural to want answers immediately.

But remember:

The ultrasound screen isn’t the final interpretation.

Your healthcare provider reviews the findings and determines what they mean within the context of your pregnancy.

From the Sonographer to the Parent on the Table

If you’re having a BPP, you may be bringing more emotion into that room than anyone realizes.

You may be hopeful, nervous, exhausted, or simply ready for reassurance.

Whatever you’re feeling, you don’t have to pretend you’re completely calm.

Ask questions.

Tell your healthcare team when you don’t understand something, and try not to interpret the examination by watching the sonographer’s face or counting how many minutes you’re on the table.

Let the examination be the examination. Let your healthcare provider explain the results.

What I Want You to Remember

A BPP may feel like another test, another appointment, and another reason to worry.

But from my side of the screen, my job is to gather the information your healthcare team needs while treating you with care and respect throughout the process. Your baby may move right away. Your baby may make us wait. You may see numbers you don’t understand. You may have questions when you leave.

That’s okay.

You don’t have to interpret everything yourself. Ask. Learn. Advocate for yourself. And remember that behind every ultrasound is a person who deserves to understand what they’re experiencing.

That’s the heart of First Hello.

Where ultrasound meets understanding.

First Hello provides educational information and does not replace individualized medical advice, diagnosis, or treatment from your healthcare provider. A biophysical profile and its components may vary based on gestational age, clinical indication, provider orders, and the testing protocol being used. A sonographer performs and documents the examination within their scope; your qualified healthcare provider interprets the findings and discusses results, recommendations, and next steps with you.