Progesterone loading as a strategy for treating postpartum depression

Postpartum depression (PPD) is a severe disorder that adversely impacts both mothers and infants. It is associated with significant morbidity and mortality and reported prevalence is 11.5% (Ko, Rockhill, Tong, Morrow, & Farr. (2017). MMWR Morbidity and Mortality Weekly Report, 66(6), 153-158). Although PPD's fundamental pathophysiology remains to be fully illuminated, the influence of changes in perinatal hormones such as allopregnanolone (an endogenous progesterone metabolite) are most promising avenues of research. Conventional treatments for PPD are aligned with treatment strategies for depressive disorders. Brexanolone is a small molecule, neuroactive steroid GABA_A receptor allosteric modulator consisting of synthetic allopregnanolone and a solubilizing agent. In early 2019, brexanolone received approval in the United States for the treatment of PPD. Brexanolone is only available through a restricted program and is costly. Animal models demonstrate that progesterone prevents depression-like behaviors. However, studies of progesterone's effects in women suffering from PPD are few and inconclusive. We hypothesize that orally dosed progesterone will increase concentrations of allopregnanolone in the central nervous system, which should relieve symptoms of PPD.