Week 24 carries a weight that most expecting parents feel acutely: this is the threshold of viability. A baby born at 24 weeks faces an extraordinarily difficult start, and survival is not guaranteed, but it is possible with intensive neonatal care. According to ACOG, viability is defined as the point at which a fetus has a reasonable chance of surviving outside the womb with appropriate medical support. That threshold is generally set at 22-24 weeks, with 24 weeks representing a meaningful marker in most clinical settings.
This doesn't mean you need to feel anxious. The vast majority of pregnancies continue well past this point. But understanding what this week means can deepen your appreciation of how far you've come.
Track your progress with our Due Date Calculator.
Your Baby This Week
Size: Corn on the cob — about 30 cm (head to toe)
Weight: About 600 grams
Your baby now weighs over half a kilogram. Here's what's most notable this week:
- The viability milestone. Survival rates for babies born at 24 weeks have improved dramatically in recent decades thanks to advances in neonatal care. Surfactant therapy, gentler ventilation techniques, and better nutritional support have all contributed. That said, babies born this early face real risks, including breathing difficulties, brain bleeds, and infections.
- Inner ear development is complete. The structures for both hearing and balance are fully formed. Sound — including your voice — is being processed in the auditory cortex.
- The brain is developing rapidly. The two hemispheres are now clearly differentiated. The brain is producing neurons at a staggering pace, and the complex wiring of the central nervous system is underway.
- Taste buds are maturing. Building on last week's developments, the gustatory system is becoming more refined.
- The lungs continue to develop. Surfactant production is ongoing, though not yet sufficient for unassisted breathing outside the womb. This will continue developing through the third trimester.
- Eyelids can now open. Although the eyes may still be mostly closed, the eyelids are capable of opening and closing, and the baby responds to bright light shone on your abdomen.
Your Body This Week
- The glucose challenge test. If you haven't had it yet, your glucose screening is likely being scheduled now or in the coming weeks. The one-hour glucose challenge test doesn't require fasting. If results are abnormal, you'll be asked to return for the three-hour glucose tolerance test, which is the diagnostic standard for gestational diabetes (ACOG).
- Fundal height. At 24 weeks, your fundal height (measured from pubic bone to top of uterus) should be roughly 24 cm. Your provider measures this at each visit.
- Carpal tunnel symptoms. Fluid retention in the wrists can compress the median nerve, causing tingling, numbness, and pain in the hands and wrists. Wrist splints worn at night are often helpful.
- Leg cramps. These often worsen in the second and third trimesters. Stretching the calf muscles before bed, staying hydrated, and ensuring adequate magnesium and calcium intake may help.
- Changes in skin and hair. Many people report thicker, faster-growing hair during pregnancy. Others notice new patches of darker skin (melasma) on the face. Melasma is triggered by hormones and worsened by sun exposure — sunscreen is your friend.
- Growing emotional complexity. It's common to feel excited and anxious in the same moment. You may be thinking more seriously about birth, postpartum life, and parenting. This is all normal, and talking about these feelings — with a partner, a friend, or a therapist — is genuinely helpful.
Tips for Week 24
1. Complete your glucose screening. Don't put this off. Gestational diabetes often has no symptoms, and untreated it carries real risks for both you and your baby, including macrosomia (large baby), preterm birth, and increased cesarean risk. Treatment — when needed — is very effective.
2. Start thinking about a birth plan. Not a rigid script, but a clear sense of your preferences: who you want in the room, your thoughts on pain management, what you'd like to happen if things don't go as planned. Writing it down helps you articulate your wishes to your care team.
3. Take a hospital or birth center tour. Many facilities offer tours and information nights for expectant parents. Knowing the layout, the policies, and who will be on your care team helps reduce anxiety when the time comes.
4. Buy a pregnancy pillow if you haven't already. Sleep disruption peaks in the third trimester, but investing in a good C-shaped or U-shaped pillow now means you'll already have good sleep habits in place before the final stretch.
5. Connect with other expecting parents. Whether through a prenatal class, an online community, or friends, social support during pregnancy is associated with better outcomes and lower rates of perinatal anxiety and depression (WHO).
When to Call Your Doctor
- Symptoms of gestational diabetes after your glucose test: excessive thirst, frequent urination beyond normal pregnancy levels, or blurred vision. Your provider will guide you on results and next steps.
- Signs of preterm labor: Regular contractions, pelvic pressure or heaviness, a dull low backache, or change in vaginal discharge before 37 weeks. At 24 weeks, every additional day of pregnancy matters.
- Decreased fetal movement: You should be feeling consistent movement by now. Any significant decrease — compared to your normal pattern — warrants a call.
- Severe swelling, headache, or visual changes — possible signs of preeclampsia; require same-day evaluation
- Fever, chills, or flu-like symptoms — infections in pregnancy need prompt attention
Related Tools & Articles
- Due Date Calculator — Calculate your estimated due date
- Pregnancy Week-by-Week Overview — full timeline
- Milestone Tracker — track your baby's development
- Hospital Bag Checklist — start planning ahead