Ask any woman about the first time she had her period and she has a story to tell such as “It was so embarrassing,” “I was the last one of my friends,” or “I thought I was dying.” While we can usually laugh about it later, we all remember the first time. But for many of us, the physiology behind the event remains a mystery.
Menstruation is the most obvious sign of puberty for girls. The average age of menstruation is about 12.5 years, but it can be a year or two earlier or later. Family history, physical development and weight give clues as to when the big day will arrive. It’s true that the average age of menarche (first period) is earlier than in previous generations. While some speculate that exposure to hormones in meat is to blame, there is no research to support this.
However, heavier than average body weight is definitely linked to earlier puberty. Similarly, very thin women may find their periods disappear. It takes a minimum amount of body fat to support the hormones that trigger menstruation.
During the weeks before a woman has her period, endometrial cells are growing inside the hollow center of the uterus. If a fertilized ovum doesn’t implant in the uterus those cells, along with blood and other fluids, are shed. Menstruation generally lasts three to five days and cycles (from the beginning of one period to the next) are typically between 21 and 35 days.
Believe it or not, the typical blood loss during a menstrual period is only four to six tablespoons, although it seems like more when you see it on your best white pants. Cramps and other PMS symptoms are part of an unwelcome package for many women. The good news is that for many women, these problems tend to subside as we get older. For some, however, cramps, pain, headaches and even nausea are unbearable. It’s not unusual for doctors to prescribe hormonal contraceptives in these cases.
The hormones that stop ovulation and prevent pregnancy also tend to make periods shorter and lighter with fewer cramps, and sometimes they even go away — what’s not to like about that? If your health care provider hasn’t discussed how your periods may change, you might be worried and think something is wrong. Generally, there’s no cause for concern. You can be perfectly healthy without having a period when you’re using hormonal contraceptives.
So how long does this carnival of fun continue? About 40 years. The average age of menopause (the time when a woman’s periods naturally stop) is 52. Menopause brings its own special delights, but that is another story for another day.