Pregnancy Ultrasound Week-by-Week: See What Happens Each Week
Last updated on December 25th, 2025 at 12:54 pm
Pregnancy brings a mix of excitement, curiosity, and the constant urge to peek inside and see how your little one is growing. Early ultrasounds often feel emotional because this is where many parents first connect with the idea of a new life forming inside them. Each week offers small but meaningful changes, and we understand those changes make the journey feel even more special.
This article walks you through what usually appears on ultrasounds from Weeks 1 to 20, along with simple explanations of how your baby grows during this time. You’ll see how tiny structures form, how the heartbeat becomes visible, and how the baby slowly starts taking shape. All descriptions are general, safe, and based on typical patterns that many pregnancies follow.
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Safety disclaimer: To keep everything clear and supportive, every ultrasound illustration in this article is used for educational purposes only. Actual scans can vary for many healthy reasons, and your healthcare provider is always the best person to guide you.
Why Early Pregnancy Ultrasounds Look So Different?
Early pregnancy ultrasounds often appear blurry, simple, or less defined because the embryo starts out extremely small. During the first few weeks, doctors focus on spotting basic structures like the gestational sac or yolk sac, which are the earliest signs of a developing pregnancy. These tiny shapes may look like dots or small round areas on the screen, and that is a normal part of early growth.
Ultrasound machines also pick up echoes differently depending on how deep the embryo is, how much fluid is around it, and how the uterus is positioned. These natural factors influence how early images appear, especially before the baby becomes large enough to show clear details.
As the weeks progress, each scan usually becomes easier to interpret. More structures form, movements become visible, and features gradually take shape.
How to Use the Images in This Guide? (Important for Safety)
The images and descriptions in this guide are meant to help parents understand how a baby typically grows in early pregnancy. These are illustrations, not real medical scans, so they only show an example of what early development may look like. Every pregnancy grows at its own pace, which means your ultrasound might show more, less, or something slightly different – and that is completely normal.
These visuals should never be used to judge health, size, or progress. Ultrasound interpretation depends on many factors, including the machine, the baby’s position, and your doctor’s assessment. The purpose here is simply to give parents an idea of what they may see during different weeks.
All illustrations included in this guide are medically safe, non-diagnostic images created for educational understanding only.
Weeks 1 to 3: What You Can Expect to See (or Not See Yet)
During the 1-3 weeks of pregnancy, it’s completely normal for the scan to look empty. That’s because these weeks are the earliest phase of conception. The body is preparing for ovulation, fertilisation happens microscopically, and the embryo is still too tiny to appear on an ultrasound.
Doctors typically do not perform scans this early unless needed for medical reasons, so most parents won’t have an ultrasound at this time.
Week 4 Pregnancy Ultrasound: The First Visible Sign
Around Week 4, some pregnancies may begin to show a tiny dark circle called the gestational sac. This is often the very first visible sign that pregnancy has started. The sac may be extremely small, and for many parents, it may not appear yet; both situations are normal because development varies greatly from person to person.
This early stage marks the start of what will eventually become your baby’s protected environment. Over the coming weeks, the sac grows, and more structures begin to appear.
Week 5 Pregnant Ultrasound
By Week 5, many pregnancies start to show clearer early structures on an ultrasound. One of the first things that may appear is the gestational sac, and inside it, a small, round shape called the yolk sac. The yolk sac supports early development until the placenta takes over later in pregnancy.
Some ultrasounds at this stage may also begin to show a tiny developing area where the embryo will grow, but it can still be too small to identify clearly. This variation is expected, and healthcare providers usually wait for the next one to two weeks to see more details.
This week is often when parents get their first visual reassurance that the pregnancy has begun to form the early building blocks of growth.
Week 6 Pregnant Ultrasound
Around Week 6, an ultrasound may begin to show more defined early structures. The gestational sac and yolk sac are often visible, and a small embryo may start to appear as a tiny curved shape beside the yolk sac.
At this stage, the embryo is still very small, so its outline may look faint or grainy on screen.
In many pregnancies, this is also the time when a flicker-like motion may be seen- often representing early cardiac activity. However, visibility can vary depending on the equipment, the pregnancy’s timing, and natural differences in development.
Week 6 is typically the moment when parents first see something that represents the start of their baby’s form, even if it still looks very tiny and simple.
Week 7 Pregnant Ultrasound
By Week 7, the embryo usually appears clearer on the ultrasound. The shape may look slightly longer, and a small head-body outline can start to form. The yolk sac is often still visible beside the embryo, supporting early development.
Cardiac activity is often easier to notice at this stage, appearing as a steady flicker inside the embryo. Limb buds- tiny early beginnings of arms and legs- may also start to show, though they often look like small bumps rather than fully formed structures.
This week gives many parents a more recognisable glimpse of early growth, even though the images still appear simple and very small.
Week 8 Pregnant Ultrasound
At Week 8, the embryo often looks more defined than in previous weeks. The head shape becomes clearer, and the body may appear slightly curved, which is typical at this stage. The yolk sac may still be visible, but the embryo now takes more visual focus.
Tiny limb buds may look more noticeable this week, though still very small. The cardiac flicker usually appears stronger and easier to detect during the scan. Overall, Week 8 shows a more structured early form, giving parents a better sense of the baby’s shape.
Week 9 Pregnant Ultrasound
At Week 9, the embryo starts looking more active and slightly larger than in the previous weeks. The head becomes more rounded, and the body begins to straighten a little. Limb buds may appear more noticeable, sometimes giving the impression of tiny arms and legs forming.
You might see small spontaneous movements during the scan, which are a normal part of early development. Internal structures continue to form, and the heartbeat is usually clear and steady at this stage. The embryo generally measures longer now, making Week 9 one of the first moments when growth feels more visible.
Week 10 Pregnant Ultrasound
By Week 10, the embryo usually looks more developed and easier to identify on an ultrasound. The head and body are more distinct, and tiny hands and feet may begin to appear as small buds. Movements may be observed, though very subtle at this stage.
The fetal outline is gradually becoming more proportionate, and the heartbeat is often strong and regular. Week 10 provides parents with a clearer sense of the baby’s shape and ongoing growth, making this scan a meaningful milestone in early pregnancy.
Week 11 Pregnant Ultrasound
At Week 11, the embryo often appears more active and structured. The head is more rounded, and the body shows gentle movements. Limbs are longer and more defined, and small hand and foot structures may be visible.
Some internal features, like the early formation of bones, can sometimes be seen, while the heartbeat continues to be strong and steady. This week gives a more recognisable view of the developing baby, helping parents see early signs of growth and activity.
Week 12 Pregnant Ultrasound
By Week 12, the fetus often begins to look like a miniature human. The head, body, and limbs are more proportionate, and movements such as stretching or gentle bending may be observed. Fingers and toes are usually forming, though still tiny and delicate.
Facial features start becoming noticeable, with small indications of the nose and mouth. The heartbeat is strong and steady, and many parents see their baby moving for the first time. Week 12 provides a meaningful view of overall development as the first trimester nears its end.
Week 13 Pregnant Ultrasound
By Week 13, the fetus often looks more like a tiny human. The head is more proportionate to the body, and limb movements become more noticeable. Fingers and toes are fully formed, and subtle movements such as stretching or bending may appear.
Facial features begin to take shape, with small hints of the nose, mouth, and eyes visible on scans. Week 13 offers parents a more recognisable view of their baby’s overall growth and activity.
Week 14 Pregnant Ultrasound
At Week 14, the fetus continues growing actively. The body stretches, the head and body are more balanced, and movements like rolling or stretching are often visible on the scan. Limbs become longer and more proportionate, giving a clearer sense of the baby’s form.
Bone development begins, and early facial expressions may start to appear. Parents can see more defined body movements, making this week an exciting stage in early growth.
Week 15 Pregnant Ultrasound
By Week 15, the fetus is more proportionate and active. The head and body continue to balance, and arms and legs move more noticeably. Fingers and toes are clearly formed, and the baby may stretch, roll, or wiggle during the scan.
Some parents may attempt early gender predictions at this stage, but these should always be confirmed later, as positioning and growth can affect accuracy. Week 15 provides a detailed view of the baby’s development and increasing activity.
Week 16 Pregnant Ultrasound
By Week 16, the baby’s bones are growing and becoming more defined, making movements like stretching, rolling, or small kicks more noticeable during an ultrasound. Limbs are longer, more proportionate, and begin to coordinate with each other. The heartbeat is strong and steady, giving a reassuring sign of early development.
Parents may notice a tiny flicker representing active motion, which can be exciting to observe. Some may attempt an early gender guess, but this should always be confirmed later, as the baby’s position and movement can affect accuracy. This week also marks a stage where the baby starts building strength and mobility, laying the groundwork for future growth.
Week 17 Pregnant Ultrasound
At Week 17, fat begins to form beneath the skin, giving the baby a slightly rounder and softer appearance. Limbs become more defined and proportional, and tiny movements like stretching arms or legs can sometimes be observed. The heartbeat is strong and regular, often visible as a rhythmic flicker on the scan.
Parents may notice more activity, such as small rolls or wiggles, which reflect growing muscle strength and coordination. This stage also highlights the continued growth of internal organs, preparing the baby for more complex movements in the coming weeks.
Week 18 Pregnant Ultrasound
During Week 18, an early anatomy review can often be performed, showing developing structures such as the spine, brain, and heart chambers more clearly. Limbs are longer and joints more visible, and hands and feet may be easier to distinguish. Facial features like the nose, lips, and eye sockets start becoming noticeable.
Movements, including stretching and gentle rolls, become more frequent and visible during the scan. This week provides parents with a detailed look at the baby’s structural development and growth trajectory.
Week 19 Pregnant Ultrasound
By Week 19, facial shapes, the backbone, and the umbilical cord are often visible on an ultrasound. Movements like kicks, stretches, and flips are clearer, giving a lively sense of the baby’s activity.
Bones continue to harden and become more defined, and organs like the heart and kidneys develop further. Parents may see finer details such as early hand and foot movements or subtle facial expressions. Week 19 provides a highly detailed view of overall growth, helping families connect emotionally with the baby’s ongoing development.
Week 20 Pregnant Ultrasound (Detailed Anatomy Scan)
Week 20 marks one of the most important scans of mid-pregnancy. This detailed anatomy scan allows healthcare providers to check the baby’s major organs, including the heart, kidneys, and brain, as well as the spine and limbs.
The placenta and umbilical cord are also carefully observed to ensure proper positioning and function. Parents may get an early glimpse of their baby’s gender, though any prediction should be confirmed later, as positioning and growth can affect accuracy.
This scan often brings excitement, reassurance, and emotional connection, as parents see a more complete view of the baby’s development. Movements such as kicking, stretching, and small rolls are usually visible, highlighting the baby’s increasing activity and growth at this stage.
Weeks 21-28 Ultrasound Scan
Between Weeks 21 and 28, ultrasounds focus on monitoring the baby’s overall growth and development rather than providing weekly snapshots. Healthcare providers measure the baby’s size, including head, abdomen, and limb lengths, to track steady growth.
Major organs continue to develop, and the scan can help ensure the heart, kidneys, and brain are forming properly. The placenta and amniotic fluid are checked to confirm healthy support for the baby. Movements like kicks, stretches, and rolls are usually more visible, giving parents a sense of the baby’s activity.
Third Trimester Ultrasound Overview (Weeks 29-40)
During the third trimester, ultrasounds focus on preparing for delivery rather than week-by-week development. Providers check the baby’s position, whether head-down (optimal for birth) or breech. They also estimate growth and fetal weight to ensure the baby is developing steadily.
If needed, blood flow or Doppler studies are performed to monitor oxygen and nutrient supply through the placenta. These scans provide reassurance about the baby’s well-being and help guide any near-delivery decisions. Like the second trimester, this overview approach prioritises safety and relevance while keeping parents informed about their baby’s progress.
Why You Don’t Need Weekly Ultrasounds (Medically Safe Explanation)
Frequent ultrasounds aren’t necessary for most pregnancies. Doctors recommend scans only at key milestones to track growth, check organs, monitor the placenta, and assess fetal position. Overusing ultrasounds doesn’t provide extra benefits and may create unnecessary anxiety.
Standard schedules usually include:
- Early scans (Weeks 1-15) for dating and initial development
- Mid-pregnancy detailed anatomy scan (Week 20)
- Third-trimester checkups for growth and positioning
Your healthcare provider schedules when to do an ultrasound based on your pregnancy. Regular checkups and planned ultrasounds give a comprehensive view without needing weekly imaging, keeping both mother and baby safe.
Tips to Make Your Early Ultrasound More Enjoyable
Ultrasound visits can be exciting and memorable when you prepare well.
- Drink plenty of water beforehand, as a fuller bladder can improve image clarity in early scans.
- Bring your partner or a support person to share the experience and capture those first glimpses of your baby.
- Wear comfortable clothing that allows easy access to your belly, and don’t worry if the images look unclear- each baby develops at its own pace.
- Relax, enjoy the bonding moment, and remember that each movement and heartbeat you see is a sign of healthy development.
Conclusion
Watching your baby grow through ultrasounds is an incredible journey, from the tiniest beginnings in the first weeks to more detailed development in the second and third trimesters. Each scan provides insight into growth, movement, and overall well-being, helping parents connect with their baby before birth.
Every pregnancy is unique, and growth timelines can vary. Ultrasounds offer snapshots of development at key stages, providing both reassurance and excitement. Embrace each moment, celebrate the milestones, and continue following your healthcare provider’s guidance for a safe and healthy pregnancy journey.
Clinic One is where many parents feel their first real connection, that tiny heartbeat and first little glimpse. It’s a place where excitement, relief, and emotion come together in one unforgettable moment.
Let us gently guide you through this beautiful beginning with care, warmth, and reassurance.
Frequently Asked Questions
At what weeks do you get ultrasounds when pregnant?
Most pregnancies include two to three recommended ultrasounds, spaced across each trimester. Typically, the first scan is done in the early weeks to confirm pregnancy, the second around the mid-pregnancy period to assess growth and anatomy, and another one may be advised later based on clinical needs. Doctors may suggest additional scans depending on symptoms, medical history, or how the pregnancy is progressing.
How many times ultrasound is done during pregnancy?
In a normal pregnancy, ultrasounds are usually done 2 to 3 times. You may receive:
- An early scan to confirm the pregnancy and estimate gestational age
- A mid-pregnancy anatomy scan to evaluate fetal development
- A later-pregnancy scan if the doctor needs to monitor growth, placenta position, or amniotic fluid
The exact number varies because every pregnancy is different, and some patients may require more frequent monitoring.
When to confirm pregnancy by ultrasound?
Pregnancy can generally be confirmed by ultrasound once the early structures are visible, which is usually around the early weeks. At this stage, the scan can detect the gestational sac, yolk sac, and sometimes the early fetal pole. Your doctor may advise the timing based on symptoms, hCG levels, or menstrual cycle accuracy.
What does a one-month pregnancy ultrasound report look like?
A one-month (very early) pregnancy ultrasound report usually describes early indicators of pregnancy.
You may see terms like:
- Gestational sac: The first structure seen inside the uterus
- Yolk sac: Supports early development
- Fetal pole (may or may not be visible this early)
- Location of pregnancy (confirming it is inside the uterus)
- Measurements to estimate early gestational age
Heartbeat detection is often too early at one month, so the report will focus mainly on confirming early development rather than detailed fetal findings.
