At 7 weeks pregnant, your baby is about the size of a blueberry and looks less like a baby and more like a tiny tadpole with a large head curled over a small body. The embryo measures roughly 10 millimeters from crown to rump, and while it’s changing rapidly on the inside, the outside still has a long way to go before looking recognizably human.
Overall Size and Shape
The embryo at this stage is dominated by its head, which makes up a large proportion of the total body. The body itself is curved into a C-shape, with a small tail-like structure at the bottom that is in the process of shrinking and disappearing. That tail developed between weeks 4 and 7 and is now narrowing, becoming translucent at the tip. By the end of this week or the next, only a short curved stump will remain before it’s gone entirely.
The overall appearance is translucent and delicate. Skin is paper-thin, and the developing structures underneath are not yet covered by the layers of tissue that will eventually make your baby look solid and opaque.
The Face Is Just Starting to Form
Facial features at 7 weeks are in their earliest stages, and they don’t look anything like a finished face. Small dark spots mark where the eyes will be, with pigment just beginning to appear in what will become the retinas. Tiny indentations on the sides of the head show where the ears are forming. The tissue that will become the upper lip and the border of the nostrils is fusing together this week, as small prominences on either side of the face grow toward each other and merge.
There’s no nose bridge, no defined chin, and no eyelids yet. The mouth is a small opening, and the jaw is still forming. If you could see the embryo up close, the face would look flat and wide, with features spread apart and only loosely sketched in.
Arms and Legs Are Paddle-Shaped
Limb development at 7 weeks is one of the more visible signs of progress. The arms, which started as tiny buds just a week or two earlier, now end in hand plates that have taken on a distinct polygon shape. If you look closely, you can see moderate notching between what will become individual fingers, like the early cuts of a cookie cutter pressing into dough. The fingers themselves haven’t separated yet, but the template is there.
The legs are a few days behind the arms in development, as is typical. Foot plates are rounded but don’t yet show the notching that the hands do. There are no toes to speak of at this point. Both arms and legs are short and held close to the body, giving the embryo a compact, curled appearance.
A Heartbeat You Can See and Hear
One of the most dramatic developments by 7 weeks is the heart. It’s been beating since around week 5 or 6, but by now it has divided into right and left chambers and is pumping at a healthy clip. The normal heart rate at 6.3 to 7 weeks falls between 120 and 154 beats per minute, which is roughly twice the resting heart rate of an adult. A rate below 120 bpm at this stage can be a concern, while rates above 155 bpm are considered unusually fast.
On an ultrasound, the heartbeat often shows up as a small flickering or pulsing light on the screen, and you can usually hear it briefly during the scan. For many parents, this is the most memorable part of an early ultrasound.
What You’ll Actually See on Ultrasound
If you have an ultrasound at 7 weeks, don’t expect to see anything that looks like a baby in the way you’re imagining. The embryo is simply too small for detailed images. You may be able to make out a general shape, or you may just see a small bright spot within a larger dark circle. Both are normal.
The most obvious structure on the screen is the gestational sac, which appears as a dark, round or oval shape surrounded by the lighter tissue of your uterus. Inside that sac, you’ll likely see the yolk sac, a small white ring or bubble that’s been providing nutrients to the embryo before the placenta fully takes over. The embryo itself sits near or next to the yolk sac and may be difficult to distinguish from it, depending on the angle and the quality of the ultrasound equipment.
Transvaginal ultrasounds produce clearer images at this stage than abdominal ones, since the embryo is so small and positioned deep in the pelvis. Even with good imaging, you won’t be counting fingers or making out a face. What you will get is confirmation of the pregnancy’s location, the presence of a heartbeat, and a general sense that development is on track.
What’s Happening Inside
Most of the real action at 7 weeks is invisible. The brain is growing rapidly, producing roughly 100 new cells per minute. The liver, kidneys, and lungs are all forming, though none are functional yet. The digestive tract is taking shape as a simple tube. Bone cells are just beginning to appear, replacing the soft cartilage scaffolding that currently makes up the skeleton.
The umbilical cord is now clearly established, connecting the embryo to the developing placenta. Blood is circulating through this cord, carrying oxygen and nutrients from your body to the embryo. The nervous system is branching out, with early nerve pathways extending from the brain and spinal cord into the limbs and trunk. None of this is visible to the naked eye or on a standard ultrasound, but it’s the foundation for everything that becomes visible in the weeks ahead.