Week 24 of Pregnancy: Your Baby Is the Size of an Ear of Corn

This article is for informational purposes only and is not medical advice. Always consult your healthcare provider with questions about your pregnancy.

TL;DR

Your baby is about 30 cm — the size of an ear of corn.
Baby's hearing is fully developed, and they're responding to sounds.
This week marks the viability milestone — a significant moment in pregnancy.
Learn the signs of preterm labor so you know what to watch for.

Your Baby This Week

At 30 cm, your baby is the size of an ear of corn and has reached a major sensory milestone: hearing is now fully developed. Your baby isn't just detecting sounds anymore — they're processing them, responding to them, and even startling at sudden loud noises. You might notice a kick or jump when a door slams or a car horn honks.

Your baby's inner ear, which controls balance, is also maturing. This means your baby is developing a sense of which way is up and which way is down as they float in the amniotic fluid. They can feel when you change positions or when you move.

The lungs are continuing their critical development. Branches of the respiratory tree are forming, and surfactant production is increasing. While the lungs aren't mature enough for breathing air yet, every day brings them closer to readiness.

Your baby's skin is still thin and translucent, but it's becoming more opaque as fat continues to accumulate underneath. The wrinkled appearance will gradually smooth out over the coming weeks as your baby fills out. Fingerprints and footprints are now fully formed — unique identifiers that will last a lifetime.

Your Body This Week

Your uterus is now about the size of a soccer ball, and it extends a couple of inches above your belly button. You've likely gained 14-16 pounds, though individual variation is wide and normal.

Glucose screening typically happens between weeks 24 and 28. This test checks for gestational diabetes — a condition that affects about 6-9% of pregnancies. The most common version involves drinking a sweet glucose solution and having your blood drawn an hour later. If results are elevated, a follow-up test may be needed. Gestational diabetes is manageable with dietary changes and sometimes medication, so don't panic if your provider brings it up.

Backaches may be intensifying as your baby grows heavier and your posture adjusts to the shifting weight. Prenatal massages, warm baths, and supportive footwear can all help. If back pain is severe or accompanied by other symptoms, let your provider know.

Swelling in the feet and ankles is probably a daily occurrence now, especially by evening. Compression socks, elevating your feet, and walking regularly can help keep fluid moving rather than pooling in your lower extremities.

Common Questions at Week 24

What does viability mean?

Viability refers to the point at which a baby could potentially survive outside the womb with intensive medical care. At 24 weeks, survival rates with NICU care have improved dramatically thanks to advances in neonatal medicine. This doesn't mean your baby is ready to be born — significant development still needs to happen — but it's a medically significant milestone.

What is the glucose screening test like?

You'll drink a very sweet glucose solution (often orange or fruit punch flavored) and sit in the waiting room for an hour before having your blood drawn. You don't need to fast for the initial screening. The drink is very sweet and can make some people feel nauseated, but the test itself is straightforward.

Is it normal to feel emotional about reaching viability?

Absolutely. Many people find the viability milestone deeply emotional — especially those with histories of loss or high-risk pregnancies. It's a moment where your baby's existence outside the womb becomes more tangible. Whatever you're feeling — relief, gratitude, fear, hope — it makes sense.

How can I tell Braxton Hicks from real contractions?

Braxton Hicks are irregular, usually painless, and stop when you change position or drink water. Real contractions come at regular intervals, get progressively closer together and stronger, and don't go away with rest. If you're unsure, time them for an hour and call your provider.

Track Every Milestone

Get personalized weekly updates, appointment reminders, and weekly insights delivered to your fingertips.

Join 2,000+ expecting parents on the waitlist

This Week's Tip

Learn the signs of preterm labor so you know what to watch for. While most pregnancies reach full term, knowing the warning signs helps you respond quickly if needed. Signs include regular contractions before 37 weeks, persistent lower back pain, pelvic pressure, changes in vaginal discharge (watery, mucus-like, or bloody), and fluid leaking from the vagina. If you experience any of these, contact your provider right away. Early recognition and treatment can sometimes delay delivery and give your baby more time to develop.

Milestone: Viability Milestone

Week 24 is widely recognized as the viability milestone — the point at which babies born prematurely have a reasonable chance of survival with intensive medical care. While no one wants their baby to arrive this early, crossing this threshold provides meaningful reassurance. Modern NICUs can do remarkable things for babies born at 24 weeks, though longer in the womb is always better. This milestone is a quiet but powerful reminder of how far your baby has come — and how resilient they already are.

Sources

American College of Obstetricians and Gynecologists (ACOG). How Your Fetus Grows During Pregnancy.
Mayo Clinic. Fetal Development: The 2nd Trimester.