On Apr. 29, 2021, researchers at the University of British Columbia (UBC) announced a study published in Cell Reports Medicine that has shown that the composition of a baby’s first poop -a thick, dark green substance known as meconium- is associated with whether or not a child will develop allergies within their first year of life.

Meconium, which is typically passed within the first day of life, is made up of a variety of materials ingested and excreted during development, ranging from skin cells, amniotic fluid and various molecules known as metabolites.

“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,” says the study’s lead author Dr. Charisse Petersen, a research associate in UBC’s department of pediatrics.

As part of the study, the researchers analyzed meconium samples from 100 infants enrolled in the CHILD Cohort Study (CHILD), a world-leading birth cohort study in maternal, newborn and child health research.

They discovered that the fewer different types of molecules a baby’s meconium contained, the greater the child’s risk of developing allergies by one year. They also found that a reduction in certain molecules was associated with changes to key bacterial groups. These bacteria groups play a critical role in the development and maturation of a vast ecosystem of gut microbes, known as the microbiota, which is a powerful player in health and disease.

Using a machine-learning algorithm, the researchers combined meconium, microbe and clinical data to predict with a high degree of accuracy (76 per cent), and more reliably than ever before, whether or not an infant would develop allergies by one year of age.

The study findings have important implications for at-risk infants, say the researchers.