 Fluctuations in the levels of allopregnanolone and the other neurosteroids seem to play an important role in the pathophysiology of mood, anxiety, premenstrual syndrome, catamenial epilepsy, and various other neuropsychiatric conditions.During pregnancy, allopregnanolone and pregnanolone are involved in sedation and anesthesia of the fetus.Allopregnanolone is an endogenous inhibitory pregnane neurosteroid.