Menstrual cycle between 45 and 55 years of age. Bleeding usually lasts around 2 to 7 days. The menstrual cycle is governed by hormonal changes. These changes can be altered by using hormonal birth control to prevent pregnancy. Each cycle can be divided into three phases based on events in the ovary (ovarian cycle) or in the uterus (uterine cycle). The ovarian cycle consists of the follicular phase, ovulation, and luteal phase whereas the uterine cycle is divided into menstruation, proliferative phase, and secretory phase. Stimulated by gradually increasing amounts of estrogen in the follicular phase, discharges of blood (menses) flow stop,
Pharmacodynamics of progesterone neuropsychiatric effects associated with the menstrual cycle (e.g., dysphoria, depression, anxiety, irritability) and postpartum period (e.g., postpartum depression), as well as in catamenial epilepsy (seizures). Low and high levels of allopregnanolone seem to have a neutral effect on mood, whereas moderate levels have a negative effect, which may underlie the symptoms of premenstrual syndrome and premenstrual dysphoric disorder that are observed in 30 to 40% of premenopausal women. This U-shaped effect on mood appears to be a common property of GABA receptor positive allosteric modulators. In contrast to oral administration, parenteral progesterone, such as with vaginal administration, avoids the first-pass