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Why is my baby’s poop this color?

BY Jenny Marder  March 12, 2014 at 4:19 PM EDT
Most colors of newborn stool are perfectly normal, doctors say. Photo by Stephanie Neal Photography.

Most colors of newborn stool are perfectly normal, doctors say. Photo by Stephanie Neal Photography.

I’d like to say that our conversations in the early weeks of parenthood focused on how to contribute most effectively to the college fund, establish healthy sleep habits and encourage muscle-building activities like tummy time. They didn’t. They were about poop.

We thought we were prepared. We’d set up the diaper pail and bought the wipes. We’d diapered dolls and teddy bears and on one occasion, a bike helmet.

What we couldn’t have prepared for were the colors. The glorious prism of colors existing in a single day’s worth of newborn poop. Yellow in one diaper, bright orange in another, and then… bright green?

How is it, I wondered, while googling “baby poop green is it normal,” for the third time that day, that something as pure and unsullied as milk goes in, and this wild feast of color comes out. And to be clear, it’s not as if mom eats carrots, and the poop turns orange, or mom eats spinach, and it goes green. No, something much more mysterious was going in our baby’s bowels.

So I turned to the experts for some answers. Jenifer Lightdale is a pediatric gastroenterologist at UMass Memorial Children’s Medical Center — a glorified plumber, she jokes. As such, she spends a lot of professional time talking to parents about poop.

“We call it stool-gazing instead of stargazing,” she said.

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No parent will ever forget meconium — the black, tarry sludge — that just pours out like liquid asphalt during the first few days of life. Meconium is a combination of the many secretions that have been building up inside the infant’s intestines while in utero. This includes swallowed amniotic fluid, cellular debris and some blood.

“It’s a distinct stool that one never has again,” Lightdale said.

Its thickness and sticky consistency are believed to help seal fluids inside the baby until birth. But this doesn’t always go as planned. In some cases, babies excrete meconium during labor. When this happens, the baby is in danger of inhaling the substance, which can result in damage to the lungs. Often this will prompt doctors to make efforts to speed up the delivery using medication or surgery.

A few days after birth, the poop starts to change. Here’s where the color comes in. Healthy newborn poop colors can range between yellow, yellow-orange, yellow-green, green and various shades of brown.

babypoopitisThe gastrointestinal tract runs from the baby’s mouth to the anus. Milk, once swallowed, travels to the sink of the stomach, where digestive juices begin the process of breaking it down. The smaller, digested pieces then migrate to the small intestine.

“That’s where all the absorption — the nutrients — are taken in,” explained Mark Gilger, pediatrician-in-chief at Children’s Hospital San Antonio. “Then whatever nutrients are not needed are passed on into the large intestine or the colon.”

Enter bile. Bile is a substance that’s made in the liver, stored in the gallbladder and then secreted into the small intestine. One of its main functions is to neutralize acid in the stomach, Lightdale said. It also aids in digesting fatty foods. And it’s the bile that gives the poop the yellow or green color, along with bacteria that lives in the baby’s gut.

It’s normal for formula-fed infants to have light brown, pasty poop, according to the Mayo Clinic, with a consistency that’s been compared to peanut butter.

And orange? “It probably is a combination of that particular baby’s bile, plus the bacteria, plus the milk,” Lightdale said. “Some of that may be this somewhat undefinable thing.”

To sum up, color is a good thing. Of concern to doctors is the poop without color. A pale, clay or ivory-colored stool can mean a lack of bile. Known as “acholic stool,” this can indicate certain kinds of liver disease, in which the bile is not getting secreted effectively into the small intestine, or a narrowing of the system that carries bile down that path.

Red or black stool can also be cause for concern. Either may indicate injury. If the injury comes from higher in the gastrointestinal tract — the stomach for example — the blood may have turned black by the time it reaches the diaper. And blood from injury occurring farther down in the small intestine or colon might come out looking bright red.

“The classic cause would be an ulcer,” Gilger said. “A sore in the lining of the intestine. That’s probably the most common.”

Allergies can also cause some bleeding, Lightdale said: “It could be that the baby’s immune system isn’t handling proteins in the diet very well, and they’re having an improper reaction. That can cause inflammation, and may be why you’re seeing blood there.”

Sometimes green poop can raise a red flag too, particularly if it’s watery like diarrhea. This can also indicate a milk allergy. Note: most baby poop is watery. We’re talking so watery that it soaks right into a disposable diaper.

But the take home message, Gilger said, is that most colors, though possibly startling, are perfectly normal.

Stool changes — a lot — in the first year of a person’s life. Newborns will have as many as 12 bowel movements a day, but that starts to slow down, drastically in some babies, by about two months. This is because the gut learns to absorb more and more over time.

Now that our baby is four months, we’re practically poop veterans. Soon he’ll be eating solids. Which means a whole new color spectrum to discuss: purples, blues and chunks of undigested food, we’re told.

I’d say we’re looking forward to puzzling over these too – except for one thing. All we talk about now is sleep. But that’s a post for another day.