A new study conducted by the researchers of the University of British Columbia (UBC) has shown that the baby’s first stool can reveal whether or not they will develop allergies within a year of birth.

The study was published in Cell Reports Medicine. The baby’s poop is a thick, dark green substance called meconium.

Senior author of the study Dr. Brett Finlay said, “Our analysis revealed that newborns who developed allergic sensitization by one year of age had significantly less ‘rich’ meconium at birth, compared to those who didn’t develop allergic sensitization.”

Meconium is typically passed within the first day of life. It is composed of various materials ingested and excreted during development, ranging from skin cells, amniotic fluid, and various molecules known as metabolites, according to Science Daily.

Lead author of the study Dr. Charisse Petersen said, “Meconium is like a time capsule, revealing what the infant was exposed to before it was born. It contains all sorts of molecules encountered and accumulated from the mother while in the womb, and it then becomes the initial food source for the earliest gut microbes.”

After analyzing meconium samples from 100 infants, the researchers discovered that the child’s risk of developing allergies is greater if their meconium contained fewer different types of molecules.

The team also found that a reduction in certain molecules in meconium was associated with key changes in bacterial groups that are important for the development and maturation of gut microbes.

Dr. Petersen explained, “This work shows that the development of a healthy immune system and microbiota may actually start well before a child is born — and signals that the tiny molecules an infant is exposed to in the womb play a fundamental role in future health.”

The team said the study findings have important implications for at-risk infants.

Co-author of the study Dr. Stuart Turvey said, “We know that children with allergies are at the highest risk of also developing asthma. Now we have an opportunity to identify at-risk infants who could benefit from early interventions before they even begin to show signs and symptoms of allergies or asthma later in life.” The article was published in Science Daily.