Most babies will have their first meconium bowel movement within 24 hours of birth, and may have several before the poop changes to a yellow color. The meconium is sticky and tar like and will generally come out in large amounts, larger than the bowel movements will be after the baby gets rid of the meconium. Unlike later bowel movements, the meconium is normally scentless, making the stickiness be the biggest obstacle for new parents.

Sometimes however a baby will pass his first meconium while still in the womb, before the mother-to-be’s water breaks. If this happens the amniotic fluid will be tinted green. In many cases of hospital births where the baby has passed meconium before birth, a special NICU team will be called when the baby is delivered in case there was ingestion of the meconium into the baby’s lungs.

If a newborn does swallow some meconium it can lead to Meconium aspiration syndrome (MAS). While it is estimated that 5%-20% of newborns pass meconium in utero, only 5%-10% of those cases result in MAS. The newborn passing meconium prior to delivery occurs most often in postdate births. It can also be caused by fetal stress during the pregnancy or during labor and delivery.

If the meconium is ingested into the baby’s lungs, three things can occur to the baby; however it does not always happen. Only a third of infants who ingest meconium need breathing assistance. The things that may occur include:

• blockage of airways
• lower gas exchange in lungs
• inflamed airways leading to pneumonia

While it is almost impossible to prevent your baby from passing meconium in utero, it should be comforting to know that it is a common occurrence that most doctors and midwives know of and can properly react too during your labor and the birth of your baby.

Solid vs. Runny
Breastfed baby stool can be all different consistencies, but it is very rarely solid and hard. Normally it is thin and runny, runny enough that many will wonder if their baby has diarrhea. Most of the time the answer is no, however if seems runnier than normal or gets a very distinct smell to it, you should call your pediatrician to make sure it is normal.

Coloring
The normal color of breastfed baby poop is a mustardy yellow color. However early on when mixed with meconium it can be dark black to any shade of green. Once the meconium is gone it is likely that your baby’s stool will change shades if you eat a large amount of a food or a food that is heavily colored. Some say that if mom eats a lot of salad, and then nurses her baby her baby’s poop may end up green. Also, once your baby starts eating baby food his poop will probably change to reflect the food he is eating. When he eats carrots, his poop may look orange; if he ate peas it could be green. The coloring of your baby’s poop will change constantly as your baby’s diet changes and as he gets older.

Timing
Some breastfed babies will have a bowel movement with almost every diaper change. Others will have one only once or twice a day. Either one is normal for a breastfed baby. It is also common for a breastfed baby to go a couple of days without having a bowel movement. If your baby has not had a bowel movement for a long period of time and you are concerned about it be sure to call and ask your baby’s doctor.

Constipation
Newborns in general will make a lot of noise when trying to have a bowel movement. This is because they are learning how to use the muscles that control pushing and holding in the poo. Until they are proficient at controlling these muscles they may grunt and groan a lot sounding like they are constipated. As long as your baby is going on their own and it is not hard, then they are probably not constipated. If you are unsure however or worried about it be sure to ask your pediatrician at your next well-check.