Background Mothers with anatomic variability (e.g., shorter, wider nipples; denser areolas) may experience breastfeeding challenges disproportionately. Research aim To examine whether variations in breast anatomy are associated with risk for early breastfeeding challenges. Methods Participants included mothers < 6 weeks postpartum. Nipple base width, nipple length, and areolar density were measured on the right and left breast separately. Experiences with early breastfeeding challenges were determined through a combination of maternal report and clinical assessment. Results Participants ( N = 119) had an average nipple diameter of 23.4 ( SD = 3.0) mm for left nipples and 23.5 ( SD = 3.0) mm for right nipples (range = 10–34 mm). Average nipple length was 8.5 ( SD = 3.2) mm for left breasts and 9.1 ( SD = 3.2) mm for right breasts (range = 5–20 mm); 35% of participants had dense areolas on the left breast and 36% had dense areolas on the right breast. The combination of wider and longer nipples was associated with greater risk for difficulties with latch; the combination of wider nipples and denser areolas was associated with greater risk for sore nipples. For participants with more dense areolas, shorter and wider nipples were associated with greater risk for low milk supply and slow infant weight gain. For participants with less dense areolas, longer and wider nipples were associated with greater risk for low milk supply and slow infant weight gain. Conclusion Further research is needed to understand how measures of breast anatomy can be used to guide targeted intervention efforts.