When Is the Best Time for a 4D Baby Scan?
By Maria Birch, UK-Registered Obstetric Sonographer
Last updated: 2nd July 2025
If you’re thinking about booking a 4D baby scan, you’ve probably asked yourself:
“What’s the best time to do it?”
Here’s the simple answer:
👉 The best window for 4D scans is between 24 and 34 weeks.
But the ideal time for most people is right in the middle—around 28 weeks.
That’s when your baby has developed enough fat stores to show facial features, but still has enough space and fluid around them for good visibility.
Still, there are a few important things to know before you book.
What Is a 4D Baby Scan?
A 4D scan is a live, moving 3D ultrasound that lets you see your baby stretching, yawning, sucking their thumb—or even smiling.
It’s often called a bonding scan, and while it’s not used for medical diagnosis, it can offer emotional reassurance and a unique glimpse into your baby’s world.
Why 28 Weeks Is Often the Sweet Spot
Around 28 weeks:
- Your baby’s face is more developed and filled out
- There’s still plenty of amniotic fluid around them
- They usually have room to move into a photogenic position
But every pregnancy is different—and scan results can vary depending on several factors.
Factors That Affect 4D Scan Image Quality
Even if you book at the perfect gestational age, a few things can still make it tricky to get clear images:
- Placenta position: If your placenta is in front of your baby’s face
- Baby’s limbs: Hands, feet, or the cord might be covering their face
- Fluid volume: Low fluid around the face can reduce clarity
- Baby’s position: Facing your spine, curled into the placenta, or head-down too early
- Maternal BMI: A higher BMI can affect image depth and sharpness
That’s why timing is helpful—but not a guarantee.
What If Baby’s Not in the Right Position?
At Sneak-A-Peek Ultrasound, we take extra time to give you the best possible experience.
If your baby isn’t in a good position, we’ll try the following:
- Ask you to move around or have a little jump
- Invite you to go for a short walk
- Offer a drink of water or something sugary
These gentle techniques often encourage your baby to shift.
And if that still doesn’t work?
✅ We offer a free repeat scan to give you another chance.
Depending on availability, you might even come back later the same day.
Not all clinics offer this flexibility, and some may rush the process. At Sneak-A-Peek, we allow 45-minute appointments so there’s time to relax, enjoy, and connect with your baby.
Is It Worth Getting a 4D Scan?
That depends on what you’re hoping for.
If you’re excited to see your baby’s face and movements before birth—and you understand that some unpredictability is part of the process—then yes, it can be a truly special moment.
You’ll leave with:
- Moving videos and images to keep or share
- A deeper emotional connection to your baby
- Reassurance that everything is progressing normally
If you’re still unsure, you’re welcome to book a Scan Clarity Call first to talk it through with me.
Summary: Best Time for 4D Ultrasound
|
Weeks |
What to Expect |
|---|---|
|
24–26 |
Early bonding, more room, but facial features less developed |
|
27–30 |
Optimal time for most—best balance of features and space |
|
31–34 |
Still possible, but baby may be tucked low or facing away |
