Question about an image 1 in your book

[Inge D]

Dear Dr. Briden, I have a question on image 1 in your book Hormone Repair Manual. It is the image about the hormones through our lifespan. My question is related to the fluctuation of progesterone during the reproductive years. Estradiol is - as expected - quite stable but why is progesterone fluctuating that much? Is that a representation of possible anovulatory cycles? I would expect progesterone also to be drawn as more stable during reproductive years... Could you clarify why? Thanks a lot.

[Lara]

It's a very schematic image of the 400 menstrual cycles and their luteal phases (i.e. the only time we make progesterone) -- so with healthy reproductive years, we make progesterone only about half the time. Plus during pregnancy, when we make an astronomical amount of progesterone.