Hi, thanks for asking in Healthcare Magic. Petogen contains Medroxy progesterone acetate. It is a progesterone. It also has a weak androgenic action. Weight gain is due to the androgenic effect of Petogen. But minimal androgenic action is beneficial in fibroids as it can shrink the fibroids. As a progesterone, Pitogen causes head ache, breast engorgement and mood swings. Drugs may not give adequate relief in fibroids and surgery is the best option. However drugs like Danazol and GnRH analogs (Nafrelin) can shrink the fibroids. Progesterone reduces heavy bleeding during menstruation it reduces the size of fibroids minimally. Although you have not mentioned about it, probably you had heavy bleeding during period due to multiple fibroid, so Petogen has been prescribed for you. But if the side effects are severe, then you will have to either stop it or switch over to progesterons with no androgenic action like Gestodene after consulting with your treating Dr. Danazol may not be suitable for you as it will further increase your weight and will cause ammenorrhea (absence of period). GnRH analogs reduce estrogen and progesterone level and may shrink the fibroid but will cause ammenorrhea. I hope this is useful to you.