The human menstrual cycle is a hormonally regulated system that controls female reproduction and fertility. Like the phases of the Moon, it has a periodicity of approximately 28 days. As different hormones switch on and off throughout the cycle, different physiological and emotional events occur. One of these events is ovulation, the time when a woman is most fertile and therefore most likely to conceive. By knowing her ovulation symptoms, a women can more easily decide whether or not to have intercourse to either avoid or enable conception.
The first day of each menstrual cycle is defined as the day that bleeding begins. Bleeding takes place over several days and represents the time when the uterine lining, the endometrium, is shed. This is called menstruation, and it is the most obvious time point in the entire cycle. The menstrual period provides evidence that conception has not taken place. Back in the previous century, it was not possible for a women to confirm whether or not she was pregnant until her period was two weeks late. By this time, according to the above definition, she would be six weeks' pregnant.
The human female reproductive cycle occurs in three phases. The 'first' phase is called the follicular phase, prior to release of the ovum, or egg. By definition, this is the first day of bleeding, called menstruation. This is when a hormone called follicle-stimulating hormone (FSH) is at it highest level. FSH triggers the release of a number of ovarian follicles, each containing a single egg. When the levels of FSH go down, one of the follicles continues to develop and it begins to produce another hormone, estrogen.
In the second phase, ovulation, levels of a third hormone, leutenizing hormone (LH) are at their highest. The follicle releases the egg and estrogen levels are at their highest level. Once the ovum has been released, the remaining follicle undergoes closure and transformation into a body known as the corpus luteum. The corpus luteum starts to secrete the fourth hormone, progesterone. Together, estrogen and progesterone now work in tandem to cause the lining of the uterus to become thick and ready to nurture the potential products of conception.
Fertilization may take place up to twelve hours after the egg is released. Conception is more likely to occur if sperm are already resident in the reproductive tract prior to release of the ovum. If conception does not take place, the thickened lining is not required to nourish the fertilized egg or zygote, and the lining is discharged during Day 1 of the next menstrual cycle.
There are a number of ways that a women may determine whether or not she is in the ovulatory phase of her menstrual cycle. One of these is to buy a kit from the drug store that measures LH (in the urine) or rising estrogen levels (by testing the saliva).
During ovulation, raised levels of estrogen cause the saliva to become saltier. When viewed under a microscope, the dried crystals of salt yield a fern-like pattern. Kits that test the saliva consist basically of miniature microscopes through which the user may observe this pattern, called salivary ferning.
There are two ovulation symptoms that do not require the use of a tiny chemistry set. One is a series of sharp, one-sided pains in the abdomen, termed 'Mittelschmerz'. These may last for a few moments or for a matter of days. The other symptom is a change in the appearance and consistency of the cervical mucous. Normally thick and creamy looking, it takes on a clear, stringy character during the ovulatory phase of the cycle. When a woman is able to determine when she is likely to conceive, she can then choose to have intercourse, or not, depending on whether she wishes to conceive a child.
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