A new IV drug was just released for the treatment of Postpartum Depression.  Called Brexanolon (Zulresso),  it requires a continuous infusion over 60 hours. 

Brexanolone's mechanism of action is different from that of currently available antidepressants. It is chemically identical to endogenous allopregnanolone, a hormone that decreases after childbirth. Brexanolone acts as a positive allosteric modulator of gammaaminobutyricacidA(GABAA) receptors, which become dysregulated in the postpartum period.

Side effects in MOMS include excessive sedation and sudden loss of consiousness during administration.  Unfortunately, we do not know of levels of allopregnanolone in human milk. 

We'll probably have to wait some months before this product is released.