“A menstrual period is a failed pregnancy.”
Several years after I graduated from medical school, I happened to meet one of my classmates and he told me the following story. He had gone to Jackson Memorial Hospital – a large county hospital in Miami, Florida for his internship and residency. One night, while on duty in the emergency room, a woman came in complaining of vaginal bleeding and she was concerned about it.
He examined her and came to the conclusion that she was probably having a normal menstrual period. The reason for her concern? She had never had one and she was 42 years old. The reason? She had 23 children! This woman was either pregnant or breast-feeding her entire adult life and never experienced a menstrual period.
It is a sad commentary on our educational system that women are so poorly educated and so badly misinformed about the normal functioning of their reproductive tract. Recently, “Good Morning America” had a segment discussing a “new” therapy whereby women would go on long-term continuous birth control pills to stop their period. As a preliminary to this segment, they interviewed a number of women on the street. Their comments about their menstrual cycles and what they believed to be true was sad and more than a little frightening. It did not help the situation any that Dr. Nancy Snyderman, Good Morning America’s medical consultant for women’s health, had many of her facts wrong as well. We hope that this pamphlet provides you with the facts necessary to understand exactly what is happening to your body every month and to help you make intelligent decisions if something goes awry.
Abnormalities of menstruation constitute one of the three most common reasons women seek medical care – other than a routine check-up. The other two principal problems that would compel a woman to call her physician for something other than a routine check-up would be either pain or an annoying vaginal discharge.
This pamphlet is designed to help you understand this entire process, which is so universal and yet so poorly understood by the women who experience it. It will also try to clear up the many myths that surround menstruation.
The female reproductive tract has one and only one purpose — to make babies. Everything that happens to a woman under normal circumstances is done with that goal in mind.
To understand not only the reasons for abnormal menstrual cycles but also the rationale for therapy, it is necessary to understand what happens to a woman during a normal menstrual cycle.
In a normally ovulating woman, each month an egg begins to grow and develop within a structure called the follicle. The follicle is comprised of the egg and the surrounding ovarian cells that are necessary for the growth and development of the egg. The cells of the follicle wall also serve as the source of estrogen which is produced during the menstrual cycle.
The brain controls the menstrual cycle as it controls every bodily function. The hypothalamus is the part of the brain that controls the endocrine system. The hypothalamus produces a hormone, Gonadotropin Releasing Hormone (GnRH) , which makes the pituitary gland produce, store, and eventually release FSH and LH, the two hormones which control the ovary. The ovary (and the testicle) are the gonads; hence, FSH and LH are called Gonadotropins.
As the follicle develops, fluid begins to collect inside it and at the time of ovulation when the follicle is fully developed, the follicle is approximately 1 inch (25 millimeters) in diameter and contains about 1/2 teaspoon of fluid. The follicle is, by strict definition, a small cyst. Because of the fluid which the follicle contains, it is easy to visualize it on ultrasound and this, of course, is very important in tracking an infertile woman during her menstrual cycle.
Once the follicle has reached full maturity, the follicle wall ruptures and the egg is expelled. This is the process of ovulation.
As the follicle matures, estrogen is produced in increasing amounts. The estrogen level peaks and then falls. Approximately 12-16 hours after the estrogen level peaks, the pituitary gland releases a very large amount of LH – an event called the LH SURGE. It is this release of large amounts of LH that can be detected in the urine by the home ovulation kits sold in drugstores.
The LH surge triggers ovulation. Ovulation occurs 12-16 hours after the LH surge. The LH surge also serves to initiate the transformation of the follicle into the corpus luteum.
After the egg is released from the follicle, it is picked up by the fallopian tube. Fluid accumulates in the deep pelvis behind the uterus where it can be seen on ultrasound. This is one of the indicators that ovulation has occurred.
After ovulation takes place, the follicular cells undergo a transformation and the structure that was once the follicle now becomes the corpus luteum. Prior to ovulation, the follicle produces estrogen; after ovulation, the corpus luteum produces estrogen and progesterone.
If a woman conceives, the embryo spends approximately three days in the fallopian tube and then moves into the uterus where it spends another three days as a free floating structure. Then, approximately six to seven days after fertilization, the embryo implants into the endometrium and subsequently develops there.
The embryo produces a hormone called HCG. HCG tells the corpus luteum that a pregnancy has begun and maintains the production of estrogen and progesterone by the corpus luteum.
If a pregnancy does not occur, no HCG is produced and no signal is sent to the corpus luteum. In the absence of the HCG signal, the corpus luteum has a built-in life span of fourteen days. By the end of the fourteen days, as the corpus luteum is slowly dying, estrogen and progesterone production decline.
The endometrium is a hormonally dependent tissue. Without the estrogen and progesterone from the corpus luteum, the endometrium loses its hormonal support and without this support, the endometrium sloughs and bleeds. This constitutes the menstrual period.
When the entire system is working normally, maturation of the egg takes approximately fourteen days and the corpus luteum has a life span of approximately fourteen days. This gives the normally menstruating woman a menstrual cycle length of approximately twenty-eight days.
Thus, as you can now appreciate, a menstrual period occurs only under normal circumstances when conception has not taken place. Therefore, if you wish to look at menstrual periods from a purely functional viewpoint, nature never really intended women to have menstrual periods.