What Can You See Week by Week During Your Pregnancy Scan?

3D pregnancy scan.

There's nothing quite like the excitement of seeing your baby for the first time on an ultrasound screen. As an expecting mum, you're probably wondering what exactly you'll be able to see during those precious scan appointments, and how your little one will change from week to week. The truth is, baby scans offer an incredible window into your child's development, revealing amazing details about their growth journey that would have been impossible to see just a generation ago. 

From confirming your pregnancy to watching tiny fingers and toes form, each scan tells a unique story about your baby's development. Let's explore what you can expect to see during different stages of your pregnancy, and how these magical moments can help you bond with your bub before they arrive. 

First Trimester: The Foundation Stage (Weeks 4-12)

During your first trimester, scans primarily focus on confirming pregnancy and establishing key dates. While your baby is still tiny, there's plenty to discover.

Weeks 4-6

At this stage, your baby is about the size of a poppy seed or a grain of rice.

• Gestational sac - The first sign of pregnancy, appearing as a small dark circle

• Yolk sac - Provides early nutrition for your developing embryo  

• Fetal pole - The earliest visible sign of your baby's body 

Weeks 7-9

Your little one is now roughly the size of a blueberry.

• Heartbeat detection - Usually visible from around 6-7 weeks, this is often the most emotional moment for parents  

• Basic body structure - Head and body regions become distinguishable  

• Limb buds - Early formation of arms and legs begins to appear 

Weeks 10-12 

Your baby has grown to about the size of a cherry.  

• Defined head shape - Your baby's head becomes more proportioned  

• Facial features - Eye sockets, nose, and mouth start to form  

• Movement - Your baby may be moving, though you won't feel it yet  

• Crown-rump length - Accurate dating measurements can be taken

Second Trimester: The Detail Stage (Weeks 13-27)

The second trimester is when scans become truly spectacular. Your baby's features become much clearer, and this is typically when detailed anatomy scans are performed.

Weeks 13-16 

For these weeks, your baby is now about the size of a lemon.  

• Gender determination - From around 15-16 weeks, gender can often be determined  

• Skeletal development - Bones begin to harden and become visible  

• Organ formation - Heart chambers, kidneys, and other organs can be examined  

• Proportional growth - Your baby's body becomes more proportionate 

 Weeks 17-20 (Anatomy Scan) 

Your little one has grown to roughly the size of a small banana.  

• Detailed organ examination - Heart, brain, spine, kidneys, and other organs are thoroughly checked  

• Facial features - Lips, nose, and eye sockets become clearly defined  

• Limb measurements - Arms, legs, hands, and feet can be measured and examined  

• Placental position - Important for delivery planning

 Weeks 21-27 

Your baby is now about the size of a mango.  

• Facial expressions - Your baby may yawn, smile, or make other expressions  

• Hair and eyebrows - Fine hair begins to appear  

• Skin development - Skin becomes less transparent  

• Breathing movements - Practice breathing can sometimes be observed 

Third Trimester: The Preparation Stage (Weeks 28-40)

During the third trimester, scans focus on growth monitoring and preparation for birth. Your baby's features become remarkably clear, especially with 3D and 4D imaging. 

Weeks 28-32

At the start of the trimester, your baby can be compared to the size of a large eggplant.  

• Rapid brain development - Brain tissue becomes more complex and visible  

• Eye movement - Your baby's eyes may open and close  

• Distinct facial features - Nose, lips, and cheeks become well-defined  

• Positioning - Your baby begins to assume head-down position 

Weeks 33-36 

Your little one has grown to roughly the size of a pineapple.  

• Mature facial features - Your baby's face looks almost exactly as they will at birth  

• Chubby cheeks - Fat deposits create that adorable baby face  

• Detailed hand and foot images - Fingers, toes, and even fingerprints may be visible  

• Hair detail - Hair growth becomes more apparent 

Weeks 37-40 

Your baby is now about the size of a small watermelon.  

• Birth-ready appearance - Your baby looks fully developed and ready for the outside world

• Positioning for delivery - Final positioning can be confirmed

• Estimated weight - Size and weight estimates help prepare for delivery  

• Lung maturity indicators - Signs that your baby is ready to breathe independently 

Making the Most of Your Pregnancy Scan Experience

Remember that every pregnancy is unique, and what's visible during your scans may vary depending on your baby's position, your body type, and the quality of equipment used. The most important thing is that your healthcare provider can monitor your baby's healthy development. 

Consider bringing your partner or a loved one to share these special moments, and don't hesitate to ask your sonographer questions about what you're seeing. These scans are more than just medical procedures. They're your first photos together as a family, capturing precious memories that you'll treasure forever. 

Experience the wonder of seeing your baby's development! 

Book your scan with Had Me At Hello Imaging and let us help you create those wonderful first moments with your little one.

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