Meconium Formation (First Bowel Movement)
Meconium, baby's first stool, accumulates in intestines throughout pregnancy.
Development Timeline
Weeks 12-40 and postpartum
Overview
Meconium is the thick, sticky, dark green or black substance that becomes your baby's first bowel movement after birth. It begins forming around week 12 as baby swallows amniotic fluid.
Meconium consists of amniotic fluid, skin cells, lanugo, vernix, bile, and other materials baby has ingested. It accumulates in the intestines throughout pregnancy and is typically not passed until after birth.
Occasionally, babies pass meconium before or during birth (meconium-stained amniotic fluid), which can indicate stress or post-term pregnancy and requires extra monitoring to ensure baby doesn't aspirate it.
🗓️ 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
- •First diapers contain dark, tar-like meconium
- •Takes several meconium poops to clear
- •Then transitions to normal newborn stools
- •If meconium in amniotic fluid, baby monitored closely
- •Usually passes easily after birth
💡 Tips for Parents
- ✓Meconium is baby's first poop
- ✓Very thick, sticky, and dark
- ✓Normal to pass within 24-48 hours of birth
- ✓If passed in womb, can be problematic
- ✓Post-term babies more likely to pass before birth
- ✓Hospital monitors for meconium passage
🛍️ 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
Meconium is sterile - no bacteria
Contains swallowed lanugo and skin cells
Very difficult to clean off baby's skin
The word means "poppy juice" in Greek
Passing meconium before birth can indicate stress
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