Background: Labor sufentanil impact on the newborn is debatable. This randomized double-blind investigation examined the transplacental conveyance and neonatal influences of sonophoretic versus epidural sufentanil for labor analgesia and its outcome on breast-feeding. Methods: 60 Healthy parturient women receiving labor epidural analgesia were enrolled in the study. They were administered epidural bupivacaine (12-ml bolus then 10 ml/h of 0.125%) solely (Group I, n = 20) or with sonophoretically transdermally administered sufentanil (Group II, n = 20) or with epidurally administered sufentanil (Group III, n = 20). Sufentanil received by Groups II and III was 15 μm followed by 10 ml/h of 0.25 μm/ml solution. Results: Sufentanil was detected in five umbilical arterial (UA) samples in Group III versus in two UA samples in Group II. Neonatal Neurologic and Adaptive Capacity Score (NACS) at 24 h was lowest in Group III (P = 0.04). On postpartum day 1, Group III women reported breast-feeding difficultly (25%) more oftentimes than Group II women (10%), or Group I women (5%) (P = 0.05). There was 45% breast-feeding difficulty in each group according to lactation consultant’s assessment (P = 1.0). At 6 weeks postpartum, more Group III women were not breast-feeding (35%) than Group II women (10%) or Group I (10%) (P = 0.004). Conclusion: Sufentanil transplacental transport and fetal exposure appeared greater in epidural than in sonophoretic sufentanil. The former group women were facing more difficulty at starting breast-feeding on postpartum day 1 and were more apt to have stopped breast-feeding 6 weeks postpartum than the latter group women.