# Short-long term near infrared spectroscopy patterns after different milk regimens olfactory stimuli in late preterms

## TL;DR

This study examines how the smell of breast and formula milk affects brain and abdominal blood flow in late preterm infants using near-infrared spectroscopy.

## Contribution

The study introduces new insights into how olfactory stimuli from different milk types influence cerebral and splanchnic hemodynamics in late preterm infants.

## Key findings

- Breast milk odor significantly increased cerebral oxygenation and cerebral-splanchnic redistribution.
- Formula milk odor significantly increased splanchnic oxygenation and splanchnic-cerebral redistribution.
- NIRS detected early changes in cerebral and splanchnic patterns after olfactory stimuli.

## Abstract

The aim of the study is to investigate the effects of olfactory stimuli from breast and formula milk on near-infrared spectroscopy (NIRS) cerebral and splanchnic patterns in late preterm infants.

We conducted a multicenter prospective observational pretest-test study in 30 late preterm infants subjected to olfactory stimuli from breast and formula milk. Regional oxygenation status, tissue function in cerebral and splanchnic districts, and cerebral-splanchnic hemodynamic redistribution were recorded at four pre-determined time-points: before sniffing (30 min), during sniffing (30 s), short-term (30 min), and long-term after olfactory stimuli (180 min).

After olfactory stimuli from breast and formula milk we found: (i) a significant increase (p < 0.05) in cerebral oxygenation and cerebral-splanchnic hemodynamic redistribution after breast milk stimulus, (ii) a significant increase (p < 0.05) in splanchnic oxygenation and splanchnic-cerebral hemodynamic redistribution after formula milk stimulus.

The present results show early changes in NIRS patterns in cerebral and splanchnic districts after breast and formula milk stimuli. Data opens the way to further studies using NIRS as a reliable tool for central nervous system and splanchnic development and response after olfactory stimuli.

The online version contains supplementary material available at 10.1186/s13052-025-01912-0.