Progesterone is a hormone in the body that helps to control the thickness of the uterine tissue lining, according to Dr. Frederick R. Jelovsek, a physician writing on Women's Health Resource. This means progesterone plays a vital role in menstruation and ceasing menstrual bleeding. Women who have low progesterone levels may bleed too much during menstruation. However, women with high progesterone levels can experience negative effects as well.
High progesterone levels can send signals to the brain to slow down receptor messages. For this reason, progesterone may be used in those with epilepsy to decrease seizure contractions, according to Dr. Jelovsek. For some women, excess progesterone can take on a sedative-like effect and cause them to feel lethargic.
Progesterone levels affect the balance in a woman's uterus and menstrual cycle. When too much progesterone is produced, the excess hormone can cause ovarian cysts to grow, according to Lab Tests Online. Because there are other causes related to ovarian cyst development, a doctor may order a blood test for progesterone levels to determine if the hormone could be causing cysts to form.
Throughout your menstrual cycle, your progesterone levels fluctuate, according to Net Doctor. A woman should reach her highest point of progesterone around seven days before she starts her period---a point also known as ovulation. At this point, a woman's progesterone level may reach up to 20 ng/mL, according to Natural Hormones. If a woman's progesterone levels are not high at this time or do not fluctuate at all, she may have a difficult time getting pregnant. If you are trying to get pregnant, a physician may measure your progesterone levels to ensure they are fluctuating enough in order for fertilization to take place.
Progesterone levels rise significantly during pregnancy, according to Natural Hormones. Your physician will monitor your progesterone levels at this time and will possibly prescribe progesterone therapy if your levels are not high enough. Especially high levels during pregnancy, however, can indicate the development of multiple births, including twins or triplets.
High progesterone levels can also produce symptoms such as vaginal dryness, depression and lack of interest in sex, according to Diagnose Me. Breast tenderness is also associated with excessive progesterone levels.