Differences in infant feeding practices by mode of conception in a United States cohort

Objective: To identify associations between fertility treatment use (assisted reproductive technologies, ovulation induction, and artificial insemination) and subsequent infant feeding practices. Design: The Upstate KIDS population-based cohort enrolled mothers who delivered live births in New York (2008-2010), sampling on fertility treatment and plurality. Setting: Not applicable. Patient(s): Data regarding singletons and one randomly selected infant between twins were used. Intervention(s): Not applicable. Main Outcome Measure(s): Mothers reported breast feeding and formula feeding practices at 4, 8, and 12 months postpartum. Modified Poisson regression was used to compare risks for feeding practices by mode of conception. Marginal structural models were used to estimate the controlled direct effects of fertility treatment on feeding, independent of preterm birth. Result(s): Among 4,591 mothers, 1,361 (30%) conceived with the use of fertility treatments. Mothers who used fertility treatments were less likely to breast feed to 12 months after birth and were more likely to provide formula, solids, and juice by 4 months than mothers who did not conceive with treatments. Fertility treatment remained associated with breast feeding cessation and formula feeding in mediation analyses, suggesting that preterm birth does not fully explain these associations. Conclusion(s): Women who conceived with the use of fertility treatments were less likely to breast feed later in infancy and were more likely to provide formula, solids, and juice earlier in infancy. Our analyses accounted for confounding and preterm birth, but other contributing factors may include difficulties feeding twins or workplace breast feeding accommodations. (C) 2016 by American Society for Reproductive Medicine.