Week 24: Viability Milestone
An important milestone — at 24 weeks, your baby has reached viability. The lungs are producing surfactant, a substance needed for breathing air after birth.
Medically reviewed by Samantha L. Fox, RN, BSN, MSN
Nursing Informaticist · United States Navy Nurse Corps · Last reviewed
Your baby is the size of a...
🌽 Corn on the Cob!
👶 Baby Development
- ✓Baby has reached viability outside the womb
- ✓Lungs producing surfactant for breathing
- ✓Brain is growing rapidly
- ✓Baby is gaining about 90 grams per week now
- ✓Skin is becoming less transparent
- ✓Inner ear is fully developed — baby has equilibrium
💊 Common Symptoms
- •Glucose tolerance test time (gestational diabetes screening)
- •Carpal tunnel symptoms may worsen
- •Dry, itchy skin on belly
- •Difficulty sleeping — hard to get comfortable
- •Braxton Hicks becoming more frequent
- •Backaches and hip pain
🩺Clinical Context — From a Nurse's View
Twenty-four weeks is the traditional 'viability' threshold — survival rates with full NICU support climb to 60-80%. The other big milestone this window: gestational diabetes screening, typically at 24-28 weeks. The standard is the one-hour glucose challenge — drink 50 g of glucose, blood draw at one hour, abnormal if ≥130-140 mg/dL depending on your provider's cutoff. Fail the one-hour and you go to a three-hour confirmatory test. Roughly 10% screen positive on the one-hour, and about 6-8% of pregnancies have gestational diabetes by current criteria (ACOG 2018). Treatment is diet and glucose monitoring first, then metformin or insulin if levels stay high. Untreated GDM increases the risk of macrosomia (large baby), shoulder dystocia at delivery, and neonatal hypoglycemia. Screening is non-negotiable — don't skip it because the drink is unpleasant.
Written by Samantha L. Fox, RN, BSN, MSN — Emergency Department nurse, US Navy Nurse Corps officer.
🚨 When to Call (or Go to the ER)
- !Regular contractions more than 4-6 per hour — call
- !Vaginal fluid leak — call
- !Decreased fetal movement — call
- !Severe headache, vision changes, RUQ pain, swelling — call (preeclampsia)
- !Bleeding — call
✅ Normal — Even If It Feels Worrying
- ✓Itchy, dry belly skin
- ✓Frequent Braxton Hicks
- ✓Restless legs at night
- ✓Difficulty getting comfortable for sleep
✅ To-Do This Week
- Take the glucose tolerance test (very important!)
- Start doing kick counts daily (10 movements in 2 hours)
- Use moisturizer or belly oil for itchy skin
- Set up the car seat (practice installation)
- Tour the hospital or birth center
- Discuss emergency plans with your partner
🩺 Questions for Your Doctor
- ?What do the glucose tolerance test results mean?
- ?Do I have gestational diabetes?
- ?How should I track kick counts?
- ?Is the baby's lung development on track?
- ?What happens if I go into preterm labor?
- ?Should I start thinking about the birth plan now?
📚 References
- [1]ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol. 2018;131(2):e49-e64.
- [2]ACOG Practice Bulletin No. 222: Gestational Hypertension and Preeclampsia. Obstet Gynecol. 2020;135(6):e237-e260.
- [3]ACOG Practice Bulletin No. 234: Prediction and Prevention of Spontaneous Preterm Birth. Obstet Gynecol. 2021;138(2):e65-e90.
Editorial review: Samantha L. Fox, RN, BSN, MSN. Last reviewed: see footer.
Your baby is the size of a...