Objective: To find the critical cut-off point of nipple length that facilitates success in breastfeeding.
Material and Method: The subjects were 449 postpartum women, who delivered at HRH Princess Maha Chakri Sirindhorn medical center in Nakhon Nayok province between October, 2010 and March, 2011. Data regarding nipple length and its relation to success in breastfeeding were collected and analyzed by a receiver operating characteristic curve (ROC curve). This is a graphical method of assessing the characteristics of a diagnostic test.
Results: The data shows that 7-millimeters in nipple length had been shown to be the cut-off point that facilitates successful breastfeeding. Sensitivity was at 72.5%. Specificity was at 46.2%. The positive predictive value was at 97.8% and the negative predictive value was at 4.9%.
Conclusion: The cut-off point for nipple length that facilitates successful breastfeeding has been measured at 7 millimeters. Nurses and health personnel may use 7 millimeters of nipple length as a criteria for a successful breastfeeding screening test and give close breastfeeding support if postpartum women have less than 7 millimeters in nipple length.

Keywords: Nipple length, Latch on, Breastfeeding, Nipple problem, Short nipple