At 24 weeks, a baby in the womb is about the size of an eggplant, measuring roughly 21 cm (8.3 inches) from crown to heel and weighing around 630 grams, or about 1.4 pounds. The baby has a fully formed human shape at this point, with distinct facial features, working fingers and toes, and skin that’s visibly thin and wrinkled. This is also a major medical milestone: 24 weeks is widely considered the threshold of viability, meaning a baby born at this stage has a realistic chance of surviving outside the womb with intensive care.
Skin, Hair, and Overall Appearance
The most striking thing about a 24-week baby’s appearance is the skin. It’s wrinkled, somewhat translucent, and tends to look pink or reddish because blood flowing through the vessels beneath is clearly visible. There’s very little fat stored under the skin yet, which is why the body looks lean and the skin appears loose, almost like it’s a size too big. Over the coming weeks, the baby will gain fat rapidly and fill out.
A fine, downy hair called lanugo covers much of the body. This soft fuzz helps hold a waxy, white coating called vernix in place. Vernix acts as a protective barrier, shielding the baby’s delicate skin from the amniotic fluid it’s floating in. Both lanugo and vernix will mostly shed before birth, though some premature babies are born still covered in them. Eyebrows and eyelashes are becoming visible, and the hair on the head is starting to grow in, though it has no pigment yet.
Facial Features and Proportions
By 24 weeks, the face looks recognizably like a newborn’s. The lips, nose, and ears are well defined. The eyelids, which were fused shut for months, are beginning to part and will soon open fully. The eyes themselves are formed but the irises don’t have their final color yet. If you could see the baby’s hands up close, you’d notice tiny fingerprints already etched into the skin, along with fingernails that are still growing toward the tips of the fingers.
The head is still proportionally large compared to the body, a ratio that will gradually even out over the third trimester. The limbs are thin but well-proportioned, and the baby is active enough that most parents feel regular kicks, rolls, and even hiccups at this stage.
Movement and Sensory Responses
A 24-week baby is far from passive. You’ll likely notice patterns of activity and rest throughout the day, with some periods of vigorous kicking and others of stillness. The baby responds to sound by moving or by changes in heart rate, so a loud noise, music, or a familiar voice can trigger a reaction. Many parents find that talking or singing near the belly produces noticeable movement.
The inner ear is developed enough that the baby has a sense of balance and can tell when it changes position. Regular, jerky movements are common during this month as the baby practices coordinating its muscles. Though the eyes are just beginning to open, the baby can detect changes in light filtering through the uterine wall.
What’s Happening Inside
Some of the most important developments at 24 weeks are invisible. The lungs are in a critical phase of growth where the tiny air sacs and the airways leading to them are forming and beginning to differentiate. Cells in the lungs start producing surfactant around this time, a substance that keeps the air sacs from collapsing and is essential for breathing air. At 24 weeks, surfactant production is just getting started, which is why breathing is the biggest challenge for babies born this early.
The brain is also developing rapidly. Neural connections are multiplying, and the brain’s surface is beginning to form the folds and grooves that will become more pronounced over the third trimester. The baby has sleep and wake cycles, and brain wave patterns at this stage show distinct periods of activity that resemble dreaming.
If a Baby Is Born at 24 Weeks
A baby born at 24 weeks is extremely premature but has a survival rate between 60 and 70 percent with modern neonatal care. These babies are tiny, often fitting in the palm of an adult’s hand, and their skin may appear almost gelatinous due to how thin it is. They look strikingly different from a full-term newborn: much smaller, much leaner, and often connected to multiple monitors and breathing support equipment.
The biggest immediate challenge is the lungs. Because surfactant production has barely begun, most 24-week preemies need help breathing. When doctors know an early delivery is likely, they often give the mother corticosteroids beforehand to accelerate lung development. A baby born at this stage will typically spend several weeks, sometimes months, in the neonatal intensive care unit (NICU) as organs continue maturing outside the womb. Over time, these babies gain weight, develop the ability to breathe independently, and learn to feed, though the road varies widely from one infant to another.
How 24 Weeks Compares to Other Stages
To put 24 weeks in perspective, this is the end of the second trimester. Just four weeks earlier, at 20 weeks, the baby weighed only about half as much and the skin was even more transparent. Four weeks later, at 28 weeks, the baby will have nearly doubled in weight again, the eyes will open and close regularly, and the lungs will be significantly more developed. The third trimester is largely about gaining fat, strengthening organs, and preparing for life outside the womb.
At 24 weeks, the baby has all the basic structures it needs. What it doesn’t yet have is the insulating fat, the mature lungs, and the refined neural connections that make independent survival possible without medical support. That’s what the remaining 16 weeks of a full-term pregnancy are for.