Breastfeeding Intensity and Duration and Growth Trajectories in GDM Exposed Infants: The SWIFT Study.

BACKGROUND

Whether breastfeeding intensity, the relative amount of breastfeeding versus formula across the first year, relates to growth trajectories among infants exposed to gestational diabetes (GDM) in utero is unknown.

OBJECTIVE

To identify growth trajectory patterns and associations with breastfeeding intensity among infants exposed to GDM.

METHODS

SWIFT Offspring cohort (2009-2011) singleton, GDM-exposed infants (n = 435) born at a Kaiser Permanente Northern California hospital. Monthly summed lactation intensity ratio (sumLIR, proportion of breastfeeding versus overall feeds over 7 days). Latent class mixed models for weight-for-age (WAZ), length-for-age (LAZ), and weight-for-length (WLZ) z-scores, and skinfold thicknesses (triceps, subscapular, and sum of skinfolds). Multinomial logistic regression related sumLIR to growth trajectories.

RESULTS

A higher sumLIR throughout the first year was associated with lower odds of class membership in trajectories with accelerated growth patterns for WLZ from early infancy (1-mo OR: 0.11, 95% CI 0.02, 0.54) to 1 year (12-mo OR: 0.84, 95% CI 0.75, 0.95), as well as a lower likelihood of having accelerated WAZ growth after 6-months (12-mo OR: 0.91, 95% CI 0.84, 0.98), but not skinfold trajectory classes.

CONCLUSIONS

Higher sumLIR was associated with more favourable growth trajectories, suggesting that continued breastfeeding, even when combined with infant formula, may benefit growth among GDM-exposed infants.