Pilot Randomised Trial of Calibrated Formula Volumes to Optimise Growth in Infants at Risk for Overweight: The Califormula Randomised Clinical Trial

Background

Formula feeding and having a mother with overweight are associated with overweight during infancy.

Objectives

We sought to pilot test calibrated formula feeding guidance using age and weight specific intake recommendations to improve weight outcomes amongst at‐risk infants.

Methods

Exclusively formula fed newborns with birthweight ≥ 50th percentile delivered to mothers with pre‐pregnancy body mass index (BMI) ≥ 25 kg/m ² were randomised to intervention and usual care groups. At monthly visits from 1 to 5 months, mothers of intervention group infants with weight‐for‐length (WFL) ≥ 75th percentile were advised to give 10% less daily formula than required based upon sex, age and weight. The primary outcome was conditional weight gain (CWG) between birth and 6 months. Secondary outcomes included WFL z ‐score and overweight (WFL ≥ 95th percentile) at 6 months, as well as growth trajectory.

Results

Sixty infants were enrolled; 36 mothers (66.7%) had pre‐pregnancy BMI ≥ 30. Seventeen (28.3%) withdrew before 6 months. At each assessment, a minority had WFL ≥ 75th percentile required to receive calibrated formula guidance. There were no group differences in CWG (intervention mean 0.27, 95% CI −0.20 to 0.75 vs. control mean −0.12, 95% CI −0.62 to 0.37; p  = 0.25) or for secondary outcomes.

Conclusions

Calibrated infant formula recommendations were not associated with growth outcomes.

Trial Registration: Clinicaltrials.gov identifier: NCT05104073 (registered October 11, 2021)