How Effective Is Brexanolone for Postpartum Depression and Related Symptoms?
Faster than placebo, though placebo also did well. By hour 60 of the infusion, 81.4% of women on brexanolone had responded, compared with 67.3% on placebo. Half of the women on brexanolone responded within 24 hours, versus 36 hours on placebo. Anxiety and insomnia also improved more with brexanolone, and those gains lasted through day 30.
This was a pooled analysis of three double-blind, randomized, placebo-controlled trials in the HUMMINGBIRD program, published in the Journal of Affective Disorders. It combined 209 adult women with postpartum depression.
Dr. Kumar’s Take
Brexanolone was the first drug approved specifically for postpartum depression. Its appeal was speed. In these trials, half the women on it responded within about a day, compared with a day and a half on placebo. It also eased anxiety and sleep problems, which often come with postpartum depression. But two in three women on placebo also responded by hour 60, so the added benefit of the drug was about 14 percentage points, smaller than the headline response rate suggests. The 60-hour IV infusion in a monitored facility was also a heavy lift for a new mother. The analysis was post hoc, and several authors were employees of or paid by Sage Therapeutics, the drug’s maker.
Study Snapshot
This pooled analysis examined data from three double-blind, randomized, placebo-controlled clinical trials in the HUMMINGBIRD program: one phase 2 and two phase 3 trials. Women received a 60-hour infusion of brexanolone (90 micrograms per kilogram per hour) or placebo. The researchers measured depression with the Hamilton Depression Rating Scale (HAMD-17), including its anxiety and insomnia subscales, and with a clinician’s global rating of improvement.
Results in Real Numbers
- Women studied: 102 on brexanolone, 107 on placebo.
- Depression response by hour 60 (symptom score cut at least in half): 81.4% with brexanolone vs 67.3% with placebo. That is about 14 more responders per 100 women treated, or 1 extra responder for every 7.
- Time to response: median 24 hours with brexanolone vs 36 hours with placebo.
- Clinician-rated improvement by hour 60: 81.4% vs 61.7%, again with a median of 24 vs 36 hours.
- Anxiety and insomnia: scores improved more with brexanolone than placebo from hour 24 through day 30, and more women responded on both measures.
- Limitation: the study was not designed with enough statistical power to test these secondary outcomes.
Who Benefits Most
Brexanolone (Zulresso) is no longer available in the US: Sage Therapeutics discontinued it as of December 31, 2024, and the FDA withdrew its approval effective April 14, 2025.
When it was available, it was aimed at women with moderate to severe postpartum depression who needed rapid relief, especially those whose symptoms made it hard to care for themselves or their infants. Women with prominent anxiety and sleep problems alongside depression were natural candidates, since brexanolone improved all three in these trials.
Safety, Limits, and Caveats
Brexanolone required a continuous 60-hour intravenous infusion in a certified healthcare facility with continuous monitoring. That meant a hospital stay and time apart from the infant.
Side effects included sedation and loss of consciousness, which is why monitoring was required throughout the infusion. The treatment was expensive and not always covered by insurance. Long-term outcomes beyond the immediate post-treatment period require further study.
Practical Takeaways
- Severe postpartum depression is treatable and should not wait. Talk with a maternal mental health specialist about current options.
- Zuranolone (Zurzuvae), a pill approved by the FDA in 2023, now fills the role of a drug approved specifically for postpartum depression in the US.
- Mention anxiety and sleep problems to your doctor, not just low mood. In these trials, all three improved together.
- If antidepressants are a concern during breastfeeding, raise it early so your care team can weigh the options with you.
What This Means for Maternal Mental Health
Brexanolone showed that postpartum depression, a condition that affects up to 15% of new mothers, can respond to treatment within a day or two rather than the weeks standard antidepressants usually take. The same approach carried forward to zuranolone, which acts on the same brain pathway.
The authors conclude that these data continue to support the use of brexanolone to treat adults with postpartum depression.
Related Studies and Research
- Episode 31: Depression Explained, The Biology Behind the Darkness
- Episode 32: Depression Recovery Roadmap: A Step-by-Step, Evidence-Based Plan
- Esketamine Monotherapy for Treatment-Resistant Depression
- Role of HPA Axis in Depression Across Female Reproductive Lifecycle
FAQs
How quickly does brexanolone work for postpartum depression?
In the pooled trials, half the women on brexanolone had responded within 24 hours, compared with 36 hours on placebo. Standard antidepressants usually take weeks to show effects.
Is brexanolone safe while breastfeeding?
Brexanolone treatment requires careful consideration of breastfeeding plans, and mothers should discuss the timing of treatment and feeding plans with their healthcare providers.
How long do the effects of brexanolone last?
In these trials, anxiety and insomnia scores stayed better than with placebo through day 30 after the infusion began. Individual duration may vary, and some patients may need additional treatment or maintenance therapy.
Bottom Line
In pooled data from three trials, brexanolone worked faster than placebo for postpartum depression, with 81.4% of women responding by hour 60 versus 67.3% on placebo and a median response time of 24 versus 36 hours. Anxiety and sleep improved too, through day 30. It required a 60-hour monitored infusion, and it is no longer sold in the US. Zuranolone, an oral pill, is now the drug approved specifically for postpartum depression there.
