At 7 weeks of pregnancy, your baby is roughly the size of a blueberry, measuring about 1 centimeter from the top of the head to the bottom of the rump. It doesn’t look like a newborn yet, but the basic outline of a human face and body is starting to take shape in remarkable ways.
The Face Is Taking Shape
By the seventh week, most of the facial structures can be observed in the embryo. The upper lip and the edges of the nostrils are forming as tissue folds grow together and fuse. The cheeks and corners of the mouth are also developing as separate tissue areas merge. Even the philtrum, that small groove between the nose and upper lip, is being created right now.
The eyes appear as dark spots on either side of the head, sitting wide apart. They’re covered by a thin layer of skin that will eventually become eyelids. Small depressions on the sides of the head mark where the ears will develop. The head itself is disproportionately large compared to the rest of the body, curving forward over the chest.
Limbs, Fingers, and the Tail
Your baby’s arms have progressed from tiny buds to paddle-shaped structures. Legs are slightly behind in development but following the same path. Neither hands nor feet have separated fingers or toes yet. Over the next few weeks, the paddle shapes will develop ridges called digital rays, then webbing between the digits, and by around week 10 the fingers and toes will be fully formed and distinct.
There’s also a small tail-like structure extending from the bottom of the spine. All embryos have this temporary tail early in development. It’s completely normal. The surrounding tissues gradually absorb it, and it becomes part of the tailbone. By about week 8 or 9, it’s usually gone.
What’s Happening Inside
The major internal organs and body systems are actively forming. The liver, which is proportionally huge at this stage, has already begun producing blood cells. The kidneys and digestive tract are developing, and the brain is growing rapidly, with distinct sections beginning to specialize. By around week 8, all of the major organs and body systems will be in some stage of development.
The heart is the standout performer. It’s already been beating for about a week, and at 7 weeks it’s pumping at roughly 120 to 150 beats per minute. That’s almost twice the resting heart rate of an adult. A healthy range at this stage falls between 120 and 154 bpm. The heart still has only two chambers (it will eventually develop four), but it’s circulating blood through a tiny, growing network of vessels.
What You’ll See on an Ultrasound
If you have an ultrasound at 7 weeks, don’t expect a baby-shaped image. What you’ll typically see is a dark, circular or oblong shape on the screen: the gestational sac, which is the fluid-filled space surrounding the embryo. Inside that, a small white ring or bubble is the yolk sac, which is feeding your baby nutrients and oxygen until the placenta takes over.
The embryo itself appears as a thick, whitish shape attached to the yolk sac. It may look curved or oblong. You might be able to make out the general shape of a baby, or you might not see anything that looks particularly baby-like at all. Both are normal at this stage.
The most exciting part of a 7-week ultrasound is usually the heartbeat. You’ll likely see a tiny blinking or pulsing on the screen, and your provider can often turn up the sound so you can hear it briefly. Heart rates at this point can register at 110 bpm or faster. If the baby isn’t in an ideal position, the heartbeat may be harder to detect, which doesn’t necessarily indicate a problem.
Overall Size and Appearance
The whole embryo is still incredibly small. Crown-to-rump length at 7 weeks is roughly 10 millimeters. The body is curved into a C-shape, with the large head tucked toward the chest. Skin is paper-thin and translucent, meaning you could theoretically see developing blood vessels underneath. There’s no fat layer yet, so the embryo looks almost skeletal in proportion.
Despite the tiny size, the transformation happening this week is significant. Your baby is transitioning from a cluster of cells that looked more like a comma on a screen to something with recognizable features: a face with a forming mouth and nostrils, limbs that are starting to extend outward, and a beating heart that’s visible on ultrasound. Over the next three weeks, the remaining organ systems will continue to mature, the tail will disappear, and those paddle-shaped limbs will sprout individual fingers and toes.