Breastfeeding and growth during infancy among offspring of mothers with gestational diabetes mellitus: a prospective cohort study

Background: Breastfeeding (BF) may protect against obesity and type 2 diabetes mellitus in children exposed to maternal diabetes in utero, but its effects on infant growth among this high-risk group have rarely been evaluated. Objectives: The objective of this study was to evaluate BF intensity and duration in relation to infant growth from birth through 12 months among offspring of mothers with gestational diabetes mellitus (GDM). Methods: Prospective cohort of 464 GDM mother-infant dyads (28% White, 36% Hispanic, 26% Asian, 8% Black, 2% other). Weight and length measured at birth, 6-9 weeks, 6 months and 12 months. Categorized as intensive BF or formula feeding (FF) groups at 6-9 weeks (study baseline), and intensity from birth through 12 months as Group 1: consistent exclusive/mostly FF, Group 2: transition from BF to FF within 3-9 months and Group 3: consistent exclusive/mostly BE Multivariable mixed linear regression models estimated adjusted mean (95% confidence interval) change in z-scores; weight-for-length (WLZ), weight-for-age and length-for-age. Results: Compared with intensive BF at 6-9 weeks, FF showed greater increases in WLZ-scores from 6 to 9 weeks to 6 months [+0.38 (0.13 to 0.62) vs. +0.02 (-0.15 to 0.19); p = 0.02] and birth to 12 months [+1.11 (0.87 to 1.34) vs. +0.53 (0.37 to 0.69); p < 0.001]. For 12-month intensity and duration, Groups 2 and 3 had smaller WLZ-score increases than Group 1 from 6 to 9 weeks to 6 months [-0.05 (-0.27 to 0.18) and +0.07 (-0.19 to 0.23) vs. +0.40 (0.15 to 0.64); p = 0.01 and 0.07], and birth to 12 months [+0.60 (0.39 to 0.82) and +0.59 (0.33 to 0.85) vs. +0.97 (0.75 to 1.19); p < 0.05]. Conclusions: Among offspring of mothers with GDM, high intensity BF from birth through 1 year is associated with slower infant ponderal growth and lower weight gain.