For patients who do not wish to become pregnant, but who need treatment for their disease, doctors may suggest hormone treatment. Hormone therapy is most effective when tumors are small. Hormones can come in presentations of pills, injection or nasal spray. There are several hormones used to this treatment, including a combination of estrogen and progesterone, like birth control pills, progesterone alone, Danocrine (a weak male hormone) agonists and gonadotropin-releasing hormone Birth control pills control the growth of lining of the uterus and often decrease the amount of menstrual flow. These often contain two hormones, a progestin and an estrogen. Once the woman stops taking them, return their ability to get pregnant, but symptoms of endometriosis also may return.Some women take birth control pills continuously, without using the sugar pills or placebo, which tell the body it is time of menstruation. When taking birth control pills in this manner, periods may stop completely, which can reduce pain or eliminate it completely. Some birth control pills contain only progestin, a hormone similar to progesterone. Women who can not take estrogen use these pills to reduce menstrual flow. With these pills, some women may not experience pain for several years after stopping treatment. All birth control pills may cause some mild side effects like weight gain, bleeding between periods and inflammation. The Danocrine has become the most common treatment choice, even pills or progestin combination hormone.Side effects of Danocrine include oily skin, appearance of pimples or acne, weight gain, muscle cramps, tiredness, smaller breasts, breast tenderness, headache, dizziness, weakness, flushing or a deeper voice. Women who consume Danocrine probably will only have periods once in a while, or maybe just disappear. Women who take Danocrine also must be taken to avoid pregnancy, as this can injure the developing fetus in utero. As should be avoided use of other hormones, like birth control pills, is recommended to use condoms, a diaphragm or other methods of "barrier" to prevent pregnancy. GnRH agonists (used daily nasal spray or injection applied as monthly or quarterly) prevent the body from making certain hormones to prevent menstruation. Without menstruation, the growth of endometriosis is reduced or halted.These medications can cause side effects such as hot flashes, fatigue, insomnia, headache, depression, osteoporosis and vaginal dryness. It is recommended that women continue with the administration of GnRH agonists for about six months. After those six months, the body will start having periods again and the woman could get pregnant. But after that time, about half of women experience a return of symptoms of endometriosis.