Rapid growth early in infancy is a risk factor for obesity and cardiovascular disease later in the lifespan. Evidence is limited, but both pre- and postnatal factors are associated with early rapid growth, and include high maternal BMI prior to pregnancy and excessive gestational weight gain. This research focuses on aspects of early feeding as potentially modifiable factor affecting early infant weight gain. Formula feeding mothers are randomized to receive either 5 oz of 8 oz bottles to use in feeding their infants from 2- to 16 weeks postpartum. In addition, a reference group of exclusively breastfeeding mother-infant dyads are also included. The hypothesis is that differences in feeding practices will be associated with differences in growth and that infants randomized to be fed from smaller bottles will grow more slowly that those randomized to larger bottles. Growth patterns of formula fed infants will also be compared to those of exclusively breastfed infants.

Mothers complete feeding logs, questionnaires on health history, demographics, feeding attitudes and practices. Infant growth and body composition are measured via PEA POD, and maternal anthropometrics and body composition are measured in BOD POD the laboratory at 2, 8, and 16 weeks postpartum. Primary outcome is change in weight-for-age z-scores.

Inclusion Criteria:

• pregnant or newborn aged 28 days or younger

Exclusion Criteria:

• gestational diabetes, hypertension, pregnancy/delivery complications, premature birth, low birth weight

All data is de-identified.