Liver Development & Function
Liver develops early and performs multiple vital functions including blood production.
Development Timeline
Weeks 4-40
Overview
The liver is one of the first organs to develop and one of the largest in the fetal body. It performs many critical functions during pregnancy, quite different from its adult role.
In fetuses, the liver is the main blood-producing organ from weeks 8-24. It also filters blood, stores nutrients, produces proteins, and processes bilirubin. The liver is disproportionately large in fetuses - about 10% of body weight.
After birth, bone marrow fully takes over blood production, and the liver transitions to its adult functions. Jaundice in newborns occurs when the immature liver can't process bilirubin quickly enough.
🗓️ 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
- •Liver seen on anatomy scan
- •Disproportionately large in fetus
- •Critical for fetal survival and growth
- •Transitions to adult functions after birth
- •May cause jaundice in first week
- •Functions improve rapidly in first weeks
💡 Tips for Parents
- ✓Liver is one of the largest fetal organs
- ✓Ultrasounds check liver size and position
- ✓Liver produces blood during pregnancy
- ✓Newborn liver still immature (causes jaundice)
- ✓Takes time for liver to fully mature after birth
- ✓Your liver does much of the filtering for baby
🛍️ 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
Fetal liver makes blood cells
In fetuses, liver is about 10% of body weight
In adults, liver is only 2-3% of body weight
The liver is the only organ that can regenerate
Stores iron from mother for first months of life
Related Development Topics
👶 Planning Ahead?
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