Hello, Norethisterone drug can cause side effects like breast discomfort, changes in sex drive, pre-menstrual (pre-period) symptoms, stomach ache, acne, itching, discoloration of the skin, swelling due to fluid retention, appetite changes, headache, dizziness, sleeplessness along with menstrual irregularities. In your case, this brown discharge could be due to longer menstrual bleeding with clot formation which appears as brown-red discharge. As far as pregnancy is concerned, there is no chance as the bleeding has occurred. However, to be on safe side, consult a gynecologist and get examined for both discharges and to rule out pregnancy. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Hiren Hirpara