To: Pat Thomas Re: Progesterone in pregnancy. I just reviewed a nice review on Endocrinology of Lactation IN: Mishell's Textbook of infertility, Contraception, and Reproductive Endocrinology 4th Edition. Edited by Rogerio A. Lobo. Publisher is Blackwell Science.1997. It covers rather nicely the endocrinology of pregnancy including progesterone. Remember, Progesterone is supposed to be very high during pregnancy to sustain the pregnancy and prepare the moms breasts for lactating. Immediately after delivery, the mom will need to stop the progesterone. If anything, progesterone during pregnancy might even enhance here milk supply postpartum, at least in her case. Regards Tom Hale