Table 1:

Data Collection Time Points and Measurements

Measurements	Time	Data / Variables
During NICU Hospitalization
Infant demographics and other characteristics	At enrollment	Chart: mixed data
Early life experience: Cumulative Pain/Stressor: NICU Infant Stressor Scale (NISS)	Chart review, daily	NISS scores: continuous data, does not include infant state as preterm infant states do not always align with term infant states (i.e. crying or not crying)
Early life experience: Feeding type: mother’s own milk, human donor milk, formula	Chart review, daily	Feeding type: categorical data
Early life experience: Antibiotic use	Chart review, daily	Days of antibiotic use: continuous data
Gut Microbiome: Stool samples: 16S rRNA gene; metagenomics and metabolomics	Twice / week	Microbial abundance, diversity, indicator species, functions: mixed data
Host genetic traits: buccal swab: whole exome sequencing	Once	Genetic variations, SNPs: mixed data
Neurodevelopment: NICU Network Neurobehavioral Scale (NNNS)	36–37 wks CA	13 subscales scores: continuous data, infant state taken into consideration
Follow-up Visits at 4, 8–12, and 18–24 month corrected age (CA)
Gut Microbiome: Stool samples: 16S rRNA gene; metagenomics and metabolomics	Each follow-up visit	Microbial abundance, diversity, indicator species: mixed data
Cognition, Language, Psycho-Social, Emotional and Adaptive Behavior: Bayley Scale of Infant Developmental III Test and BITSEA scale	8–12 m & 18–24 m CA follow-up visits	3 Bayley composite scores and 2 BITSEA composite scores: continuous data
Neurodevelopment: Pain sensitivity test – Von Frey test	Each follow-up visit	Pain threshold scores: continuous data, infant state taken into consideration
Other: Growth parameters, feeding and nutrition, parent interview / questionnaire.	Each follow-up visit	Mixed data
Other: Index of the Child Care Environment (ICCE), caregiver interview/questionnaire	18–24 m CA follow-up visit	Mixed data