Hello~I have been doing some research on this, I was not familiar with it, here is what I have discovered, I hope this helps:
Norcolut - General Information
A synthetic progestational hormone with actions similar to those of progesterone but functioning as a more potent inhibitor of ovulation. It has weak estrogenic and androgenic properties. The hormone has been used in treating amenorrhea, functional uterine bleeding, endometriosis, and for contraception.
Pharmacology of Norcolut
Norcolut is a synthetic oral progestin. It is used for contraception or to treat such conditions as secondary amenorrhea, abnormal uterine bleeding, and endometriosis. As an oral contraceptive, norethindrone is available as either a single agent or in combination with an estrogen.
No, it will not affect the Dorn Therapy, Dorn therapy is similar to chiropractic and if anything, the treatments should help the Nocolut work.
I hope this helps some, this is the first I have actually heard of either one. I am very familiar with chiropractors as I see one myself, I know they help, so, I am hoping the Dorn method will help you as well.