Objectives: The objectives of this study were to describe the rates of and factors associated with exclusive breastfeeding (XBR), exclusive breast feeding + breast and bottle-feeding (Ever BR), and of exclusive bottle-feeding (XBOT) from 1925-1964 among mothers of the nurse daughters in the Nurses’ Health Cohort Studies. Methods: The Nurses' Maternal Cohort Study (N= 39,743) is a retrospective cohort of the mothers of the nurse daughters who completed a questionnaire on reproductive characteristics and infant feeding. Multiple logistic regression analysis was used to estimate the adjusted odds ratios for Ever BR and XBR compared to XBOT by birth year and other covariates. Results: Ever BR rates steadily declined from 80% in the Great Depression to 37% in 1964; similarly XBR rates declined from 41% to 10%, respectively. Factors positively associated with Ever BR included: any maternal college education compared to <12 years of education and delivering a low or high compared to normal birth weight nurse daughter. Factors negatively associated with Ever BR were: smoking during pregnancy, C-section delivery, prematurity, birth orders 2+, and nurse daughters born 1940-1964. Factors differed by birth cohort, e.g. maternal education was positively associated with XBR only from 1950-64. Among the XBOT, the majority used canned evaporated milk until 1959 and then switched to commercial infant formula. Conclusions: This study documents declining rates of XBR and factors influencing infant feeding choice from 1925-1964, with results varying by birth cohort that differ from current determinants.Nutritional Science
