@Region Philbis,
Thank you Region Philbis, I'll give him a call.
If other mothers are searching and looking for the chemical explanation I found this to be the most helpful website in my search.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4582419/
Specifically this paragraph from the local anesthetic section
" Local Anesthesia (LA) The physicochemical properties of local anesthetics, when used neuraxially, are ideal because these large, polarized molecules do not cross easily into lactating ducts.3 Specifically, epidural administrations of lidocaine and bupivacaine have been shown to be safe in lactating mothers. Both were evaluated with their metabolite, pipecolylxylidide (PPX), at 2, 6, and 12 hours in breast milk and maternal serum. The authors concluded that the milk to plasma ratios were consistent with prior data, the transfer of LA and metabolite into breast milk was minimal, and LA can be safely used in breastfeeding mothers."