Ketamine to Improve Recovery After Cesarean Delivery - Part 1

Subjects in the intervention arm will receive infusion dosing as noted in arm/group descriptions at the time of cord clamping. Duration of infusion will be 12 hours. Concentrations of ketamine and ketamine metabolites (nor-ketamine, NKET; and dehydro-nor-ketamine, DHNK) are measured in maternal plasma and urine as well as breastmilk. Maternal side effects, adverse events, and efficacy endpoints will be measured over the 12 hour infusion and over 15 hours after infusion discontinuation.