A Study to Evaluate Efficacy and Safety of SAGE-547 in Participants With Severe Postpartum Depression (547-PPD-202B)

Key Inclusion Criteria: * Participants must have ceased lactating at screening; or if still lactating or actively breastfeeding at screening, agreed to temporarily cease giving breastmilk to their infant(s) from just prior to receiving study drug through nine days (Day 12) after the end of the infusion * Participants had a major depressive episode that began no earlier than the third trimester and no later than the first 4 weeks following delivery, as diagnosed by Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) * Participant had a HAM-D total score of ≥26 at screening and Day 1 (prior to dosing) * Participant was ≤6 months postpartum at screening * Participant was amenable to IV therapy Key Exclusion Criteria: * Active psychosis * Attempted suicide associated with index case of postpartum depression * Medical history of bipolar disorders, schizophrenia, and/or schizoaffective disorder. Note: Other protocol-defined inclusion/exclusion criteria applied.