Lung Maturity & Surfactant Production
Lungs are last major organs to mature, with surfactant production critical for breathing after birth.
Development Timeline
Weeks 16-40
Overview
The lungs are among the last organs to fully mature, which is why premature birth respiratory problems are common. Lung maturity involves both structural development and production of surfactant, a substance that keeps air sacs open.
Surfactant production begins around week 24 but isn't adequate until closer to week 34-36. Without enough surfactant, lungs collapse after each breath, making breathing exhausting and life-threatening.
This is why corticosteroids are given to mothers at risk of preterm delivery - they accelerate surfactant production. Even babies born late preterm (34-36 weeks) may need breathing support as lungs finalize maturation.
🗓️ Week-by-Week Milestones
Tap any week to open its full pregnancy guide — baby size, symptoms, and what else is developing that week.
👀 What to Expect
- •Baby practices breathing movements in womb
- •Lungs filled with fluid until birth
- •First breath expands lungs and clears fluid
- •Crying helps establish breathing
- •Lungs continue maturing after birth
- •Preemies face respiratory challenges
💡 Tips for Parents
- ✓Lungs are last major organs to mature
- ✓Preterm babies often need breathing help
- ✓Steroids given to mothers speed lung maturity
- ✓Every week in womb helps lungs mature
- ✓Even 34-36 week babies may need support
- ✓Full term means lungs are ready
🛍️ Supplements & Reads for This Development Stage
Comfort and preparation products other expecting parents find helpful at this stage. These are convenience picks, not medical advice — always follow your provider's guidance.
Prenatal Vitamins (with Folate & DHA)
Daily folate, iron and DHA support that doctors recommend before and throughout pregnancy.
Check Price on Amazon →DHA Omega-3 Supplement (Prenatal)
Doctors recommend DHA throughout pregnancy for baby's brain and eye development — especially the third trimester.
Check Price on Amazon →What to Expect When You're Expecting
The classic week-by-week guide trusted by millions of expecting parents.
Check Price on Amazon →Amazon Associates Disclosure: As an Amazon Associate, we earn from qualifying purchases at no extra cost to you. These recommendations are editorially chosen comfort and preparation products and are not medical advice.
✨ Amazing Facts
Babies practice breathing but don't breathe air in womb
Surfactant prevents lungs from collapsing
First cry helps inflate lungs completely
Lungs continue developing into childhood
Premature birth was often fatal before surfactant replacement therapy
Related Development Topics
👶 Planning Ahead?
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