Oral Progesterone Conversion To Allopregnanalone Cocerns?

I was watching a YouTube video by Dr. Gersh and she was saying that most of the oral progesterone that we take is converted to unnaturally high levels of allopregnanalone in the brain. She said some studies in mice show that could contribute to dementia in the mice. I haven’t seen the studies myself but I was wondering if that is a concern we should have or a reason to switch to vaginal applications. Has anyone else heard this or read any studies?