At 24 weeks pregnant, your baby is about 12.5 inches long from head to heel and weighs roughly 1.3 to 1.5 pounds (around 630 grams). That’s about the length of an ear of corn. While size is probably what brought you here, a lot is happening inside your baby right now, and 24 weeks is a significant milestone in pregnancy for several reasons.
Weight, Length, and How They’re Measured
You may notice different numbers depending on where you look, and that’s because there are two ways to measure a fetus. Crown-to-rump length, which measures from the top of the head to the bottom of the buttocks, is about 8.25 inches (210 millimeters) at 24 weeks. Crown-to-heel length, which includes the legs, puts your baby at roughly 12.5 inches. Ultrasound technicians typically use the crown-to-rump measurement earlier in pregnancy, then shift to estimated weight as the baby grows.
Weight at this stage averages around 1.3 pounds, though healthy babies can measure slightly above or below that. Your baby will roughly triple in weight over the next 10 weeks and gain most of their body fat in the third trimester. Right now, the skin is still thin and somewhat translucent, with very little fat underneath.
What’s Developing Inside
Size is only part of the picture. At 24 weeks, your baby’s lungs are beginning one of their most critical transitions. Specialized cells in the lungs start producing a substance that keeps the tiny air sacs from collapsing, a process that began around 20 weeks and will continue maturing all the way to full term. These cells contain small storage structures called lamellar bodies, which first appear between 20 and 24 weeks and gradually increase in number and size as the pregnancy progresses. The lungs are far from ready for breathing air on their own, but the groundwork is actively being laid.
Your baby’s ears are also developing rapidly. By 24 weeks, the structures of the inner ear have matured enough that your baby is becoming more sensitive to sound. The noises they hear most clearly right now are internal: your heartbeat, blood flowing through the umbilical cord, air moving through your lungs, even your stomach digesting food. External voices and music can reach them too, though muffled by the amniotic fluid and your body.
Movement You Can Feel
Most women feel their baby’s first movements somewhere between 16 and 24 weeks, with first-time mothers often noticing them closer to the 20-week mark. Early movements tend to feel like gentle fluttering or swirling. By 24 weeks, those sensations are usually more distinct, and you may start to recognize kicks and jerky motions.
If this is your first pregnancy and you haven’t felt any movement by 24 weeks, let your midwife or doctor know so they can check the baby’s heartbeat. There’s no set number of daily movements to count at this stage. What matters more is getting familiar with your baby’s pattern over time, so you’ll notice if something changes later in pregnancy.
Why 24 Weeks Is a Medical Milestone
Twenty-four weeks is widely recognized as a threshold for viability, the point at which a baby born early has a meaningful chance of survival with intensive medical care. A large study of nearly 11,000 premature births found that survival rates have been climbing steadily. At 23 weeks, about 55% of babies who received active treatment survived. By 24 weeks, the odds improve further, though the exact percentage varies by hospital and the resources available.
Survival, however, is only one part of the picture. Among babies born between 22 and 26 weeks who were evaluated at age 2, roughly half showed mild or no neurodevelopmental issues. About 29% had moderate disabilities, and 21% had severe impairments. Around 8% were diagnosed with moderate to severe cerebral palsy, and about half of all survivors needed at least one hospital readmission after leaving the neonatal intensive care unit. Every additional week a baby stays in the womb dramatically improves these outcomes, which is why full-term delivery remains the goal.
Changes in Your Body
Your uterus has grown well past your belly button by now. A common way providers track this growth is by measuring fundal height, the distance from your pubic bone to the top of your uterus. After 20 weeks, that number in centimeters roughly matches your week of pregnancy. So at 24 weeks, you can expect a fundal height of about 24 centimeters. A measurement that’s significantly higher or lower may prompt your provider to take a closer look with an ultrasound, though slight variations are normal.
The Glucose Screening Test
Sometime between 24 and 28 weeks, you’ll likely be offered a glucose screening test to check for gestational diabetes. The most common version doesn’t require fasting. You drink a sweet liquid containing glucose, sit for an hour, and then have your blood drawn. If the result comes back high, you’ll be asked to return for a longer follow-up test that involves fasting overnight, drinking a second glucose solution, and having your blood drawn three more times over three hours. Some providers use a one-step version that combines both into a single fasting test with two blood draws after the glucose drink. Your provider may test you earlier than 24 weeks if you have risk factors for diabetes or if routine urine tests have shown elevated sugar levels.