["To investigate primiparous women's primary reason for not breastfeeding.", 'We used the 1995 National Survey of Family Growth to analyze the breastfeeding behaviors of a national probability sample of 6733 first-time US mothers, aged 15 to 44 y. Main outcome measures in this cross-sectional study were the reasons for never breastfeeding and reasons for stopping breastfeeding using closed-ended, multiple choice questions.', 'Most commonly, women did not breastfeed because they "preferred to bottle feed" (66.3%). The most common reason for stopping breastfeeding was that the child was "old enough to wean" (35.7%), although 15%, 34%, 54%, and 78% of those women had stopped breastfeeding by 3, 6, 9, and 12 mo, respectively. "Physical or medical problem" was reported by 14.9% of women who did not breastfeed and 26.9% of women who had stopped breastfeeding, making it the second most common reason for not breastfeeding in each group. There were significant differences across racial and ethnic groups.'] Do why primiparous mothers breastfeed in the United States : a national survey?