In the group not exposed to pain medication, all ten newborns successfully self-attached and suckled. Only two, or one-third, of the six babies in the pudendal block group, and three, or one-quarter, of the twelve babies exposed to narcotic, epidural anesthetic, or some combination of narcotic, pudendal block, and epidural block, did the same. Moreover, one of the two successful breastfeeders in the pudendal block group was helped by the mother and one of the four in the combination group suckled, but was not properly latched onto the nipple.
In addition, the babies of medicated mothers cried substantially more, which the authors attributed to frustration. They also ran significantly higher temperatures, which could have been due to crying and is disadvantageous in that it means a greater expenditure of calories.
Ransjo-Arvidson A et al. Maternal analgesia during labor disturbs newborn behavior: effects on breastfeeding, temperature, and crying. Birth 28(1):5-12.