The first day of the menstrual cycle is day the woman first begins to bleed from the vagina and the last day of the menstrual cycle is the day prior to the next bleeding episode. The main reason why the menstrual cycle occurs is the rise and fall of the female reproductive hormones. This cycle causes an initial thickening of the uterine lining and development of the egg in the ovaries. The egg is released from one or both ovaries at about the fourteenth day of the cycle. The uterine lining remains thickened and the lining of the uterus becomes mature during the last fourteen days of the menstrual cycle in preparation for implantation, should the egg become fertilized. In the absence of a fertilized egg, the uterine lining breaks down and the next menstrual cycle begins. The first menstrual period is associated with physical changes such as the development of the secondary sexual characteristics and an increase in height. This is called menarche and occurs between the ages of twelve to fifteen, although it can happen earlier in life in countries where the nutrition is good and girls are not malnourished at this point in their lives. When a woman refers to her last menstrual period or LMP, she is referring to the first day at which she began to bleed in the most recent cycle. While most menstrual periods are twenty-eight days in length, healthy women can have menstrual periods that are as far apart as forty-five days. Having menstrual periods further apart than this means that the woman has oligomenorrhea. Periods occur on a regular basis except during pregnancy and breastfeeding until perimenopause, which is the few years in a woman’s life that results in a decline in fertility and an increase in menstrual irregularity. This can go on for many years until the woman enters menopause at about the age of fifty-one, although the range of time for normal menopause is about forty-five to fiftyfive years of age. If a woman doesn’t have her period and is not actively pregnant or menstruating, this is called amenorrhea. Menstruation can occur during lactation; however, the fertility level is lower than if the woman wasn’t lactating. The average time for periods to resume after pregnancy is about four to six weeks but can be much longer if the woman is breastfeeding. The change in hormones is what affects both the menstrual cycle and the symptoms associated with having a menstrual period. Most women will experience menstrual cramping that can happen in the last few days of the menstrual cycle or upon the onset of menstruation. Usually, these are mild cramps that can get better with acetaminophen or a nonsteroidal anti-inflammatory medication. Breast swelling and tenderness also occur before the menstrual period and are directly related to mild fluid retention.
Dysmenorrhea The experience of pelvic cramping with the menstrual period is also called dysmenorrhea. It occurs a day or so before the actual menstrual bleeding and continues into the first day or two after bleeding starts. The cause of menstrual cramping is ischemia of the uterine lining and 4
