Peer-reviewed article
Exploring the Early-Life Microbiomes of Preterm Infants and Their Childhood Health Outcomes (The BLOOM Study): Protocol for a Prospective, Observational Cohort Study.
Asbury MR, Guedez A, Lee J, Mercer EM, Kasaba F et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001The BLOOM Study is a prospective cohort study following preterm infants born before 37 weeks gestation in Calgary, Canada to understand how their gut microbiomes develop and relate to later health outcomes. Researchers collect stool, urine, milk and other samples from infants and mothers during the first two months after birth, then follow children at 3 months, 1 year, and 3 years of age. The study aims to identify links between early microbiome patterns and childhood conditions like asthma and neurodevelopmental delays, which preterm infants face at higher risk.
Key points
- Preterm infants have disrupted microbial colonization due to developmental immaturity and postnatal exposures, placing them at elevated risk for asthma and impaired neurodevelopment
- The study enrolled 245 participants as of May 2026, with an initial characterization of microbiome profiles for the first 105 infants published in December 2025
- Comprehensive sample collection includes maternal stool, weekly infant stool and urine in the first two months, followed by samples at 3 months, 1 year, and 3 years corrected age
- Clinical assessments include allergen skin prick tests and developmental milestone questionnaires (Ages & Stages Questionnaires, Third Edition)
- Findings are intended to identify altered microbiome patterns underlying disease risk and design intervention strategies such as microbial therapeutics for future testing
Limitations
This is a study protocol describing planned research rather than completed results, so no health outcomes or intervention effects can be reported yet. The study is observational, not experimental, so causal links between microbiome patterns and health outcomes cannot be definitively established.
Abstract
Background Establishment of the gut microbiome during the first years of life is critically important for long-term health and development. In preterm infants, microbial colonization is disrupted due to their developmental immaturity and the myriad of pre- and postnatal exposures. Unfortunately, this places them at an elevated risk for adverse health outcomes into childhood (eg, asthma and impaired neurodevelopment). Understanding the developmental trajectory of the microbiome in preterm infants, the factors predicting these microbial patterns, and the links to childhood health can offer opportunities to develop interventions and optimize health. Objective BLOOM (Begin a Life of Health With Observation and Optimization of the Microbiome) is a prospective, observational cohort study that aims to examine how early-life microbiomes shape the health and development of preterm infants into childhood (eg, asthma and neurodevelopment). Methods Infants (<37 weeks gestation) and their families are recruited from 4 neonatal intensive care units in Calgary, Alberta, Canada. Maternal stool and weekly infant stool, urine, and human milk samples are collected during the first 2 months postnatally; participants are then followed up at 3 months, 1 year, and 3 years corrected age for continued data (eg, nutrition, medications, medical history, and home environment) and sample collection (stool, urine, nasal swabs, hair, and blood). Additional clinical testing (eg, allergen skin prick test) and questionnaires (eg, Ages & Stages Questionnaires, Third Edition) are administered to assess health outcomes and developmental milestones. Results Study recruitment and data/sample collection for BLOOM commenced in 2019; as of May 2026, we have enrolled 245 participants, and recruitment is ongoing. An initial characterization of early-life microbiome profiles for the first 105 infants enrolled in BLOOM was published online in December 2025. Conclusions BLOOM is a large, comprehensive prospective cohort study and biobank aimed at measuring the microbiome development of preterm-born children. This cohort will address significant research priorities through characterizing the patterns of microbiome development in preterm infants over the first 3 years postnatally and correlating these with health outcomes (eg, immune development, asthma and allergy risks, and neurodevelopment). It is anticipated that the results can be leveraged to identify factors and altered microbiome patterns underlying disease risk, design intervention strategies (eg, microbial therapeutics) for later clinical testing, and generate novel hypotheses of possible underlying mechanisms linking microbiome development to health.