Inclusion Criteria:  Ambulatory female ≥18 years of age. Participant has a current diagnosis of postpartum depression (PPD), as confirmed by the investigator. Participant agrees not to be the primary caregiver of any dependents during the infusion and must be accompanied by another adult (other than the home healthcare provider) during interactions with their child(ren). Participant has no history of sleep apnea or any clinically significant respiratory conditions. Participant agrees to refrain from the use of central nervous system depressants, such as opioids, benzodiazepines, sleep aids and from drinking alcohol during the infusion. Participant is suitable for administration of ZULRESSO® in a home setting, as per the judgement of the investigator.  Participant's home is suitable and has necessary provisions for administration of ZULRESSO® and meets the following criteria:  safe environment for the home infusion provider staff. access to a working telephone. electricity and grounded electrical outlets. running water. access to back-up emergency services (911 service or ambulance availability). sanitary environment. Participant agrees to stay at home until the end-of-study visit has been completed, except for a medical emergency. Participant must have a negative pregnancy test at screening and on Day 1 prior to the start of the ZULRESSO® infusion.  Exclusion Criteria:  Participant has end stage renal failure. Participant has known allergy to progesterone or allopregnanolone or any excipients in the brexanolone injection. Participant is currently at risk of suicide, as judged by the investigator, or has attempted suicide associated with the current episode of PPD.