The Clues to Fertility

There are a number of different clues to show where a woman is in her fertility cycle, ie. which "phase" of fertility she is in. Ovusoft utilizes three primary ones: menstruation (menses), cervical fluid, and waking temperature (also known as basal body temperature or BBT). The characteristics of the cervix are a fourth sign that some users of FAM rely on to corroborate the first three. (Ovusoft permits you to track the characteristics of the cervix, but it is informational only and not used in any calculations.)

As an absolute minimum in the practice of fertility awareness, you only need to keep track of two of the four listed above: menstruation and temperature. Cervical fluid provides an added bonus in that it defines the onset of fertility, whereas temperature only indicates when ovulation has already taken place, perhaps too late to be of much use in achieving pregnancy. When used together, however, temperature and cervical fluid help you identify your fertile period with a high degree of accuracy.

The First Clue: Menstruation
While many people regard menstruation as the start of a new cycle, as does FAM, it is actually the end of the previous cycle. Why do we say this?

Menstruation is the process of shedding the endometrium (lining of the uterus) that had built up during the previous menstrual cycle. Therefore, it truly is the end of the previous cycle. Because it is so easy to identify, however, it has become symbolic of the start of another "period" and is used as such in Ovusoft and FAM, as well.

The endometrium is a lining of tissue on the walls of the uterus that builds up before ovulation in anticipation of the implantation of a fertilized egg. If the egg is not fertilized, it does not implant and roughly two weeks later the built-up tissue is sloughed off. The uterus will build it up again in the new cycle in preparation for the next ovulation.

The Second Clue: Cervical Fluid
Cervical fluid is an important sign in fertility awareness. The woman's body begins to secrete estrogen shortly after menstruation, which causes glands around the cervix to secrete cervical fluid. As ovulation approaches, the amount of estrogen builds, causing the body to secrete even more fluid. The increased levels of estrogen also make the cervical fluid stretchy and clear.

As the level of estrogen builds, another hormone, called lutein, is released. Lutein causes the ovaries to release the ovum. The estrogen levels decrease somewhat after ovulation, causing the cervical fluid to dry up. This drying up process normally starts on or just after the day of ovulation.

Cervical fluid has several purposes in the area of human reproduction. First, it performs a lubricating function during sexual relations. Secondly, but more importantly, it provides a friendly environment for the survival of sperm after sexual relations have taken place. Without this environment, sperm would live no longer than several hours and would be literally stopped dead in their tracks, unable to move, unable to fertilize the waiting ovum. In the presence of cervical fluid, sperm are provided with both nutrients and a conduit for movement and may live up to five days in such an environment. Therefore, in addition to providing a pathway to the ovum, cervical fluid widens the fertility window beyond the daylong life span of the average ovum and hours-long life span of the average sperm. Sexual relations taking place several days before ovulation may still result in conception due to the increased viability of the sperm in the presence of fertile-quality cervical fluid.

Cervical fluid is therefore a positive sign that fertility is increasing and may be used as such in fertility awareness. For pregnancy achievers, it provides an excellent pre-ovulation indicator, whereas temperature alone can only predict ovulation after the fact.

Cervical fluid may be observed directly, in which case you might notice the following qualities:

• Sticky – A less fertile-type of fluid, not very conducive to supporting either sperm motility or lifespan. This may correspond to a Moist vaginal sensation.
• Creamy – A lotion-like type of fluid, which can support sperm for longer periods than the sticky-quality type. This may correspond to a Wet vaginal sensation.
• Eggwhite – The most fertile quality cervical fluid, it is clear, stretchy, and slippery. This type of cervical fluid resembles raw eggwhite, hence the descriptive name. This may correspond to a Lubricative vaginal sensation.

For a detailed explanation of how to observe and tell the difference between the types of cervical fluid and vaginal sensations, please refer to Taking Charge of Your Fertility, page 78.

The Third Clue: Waking Temperature
Temperature, or more accurately, waking / basal body temperature, is another one of the body's measurements that changes in regular cycles. "Basal" body temperature simply means the temperature of your body at rest.

Your body temperature is not a consistent 98.6° F / 37° C as most people think. These figures are the body's normal high temperature during waking hours. After going to sleep at night, your body temperature gradually drops, reaching its lowest point in the early morning. As you get closer to your waking hours, your metabolism picks up again, raising your body temperature ever so gradually, and the cycle is repeated. The scale of the drop and rise of body temperature can differ from person to person, (although it is normally about 0.1° F / 0.05° C) but all people experience it to some extent or another.

When a woman ovulates, the follicle containing the ovum ruptures, releasing the egg and the hormone progesterone into the body. This hormone has several effects, for our purposes not the least of which is the raising of the basal body temperature. This increase in temperature is significant and detectable, as it typically is about 0.2 to 0.4° Fahrenheit / 0.1 to 0.2° Celsius over the course of several days. To detect this change, you will need a basal thermometer, available from most pharmacies. A standard fever thermometer is not accurate enough for our purposes here, as even a change of 0.1° F / 0.05° C is important. Therefore, an important first step in the practice of FAM is to buy a basal thermometer.

FAM looks for three temperatures that rise at least 0.2° F / 0.1° C above the high of the previous six temperatures. A "coverline" is drawn 0.1° F / 0.05° C above the highest of these six temperatures and when three successive temperatures are above this line, a thermal shift is identified and there's a good chance that ovulation has already occurred. (This is a simplification of the identification of the coverline; please refer to Taking Charge of Your Fertility or the glossary for more a more detailed explanation of calculating a coverline and identifying various thermal shift conditions.)

The temperature sign gives us a great, but late, clue that ovulation has occurred and helps to pinpoint the actual date. That's why it is so important to use cervical fluid in conjunction with temperature in the practice of Fertility Awareness if pregnancy is your goal -- together they identify when you are fertile and when ovulation has already occurred.

The Fourth Clue: Characteristics of the Cervix
The opening of the uterus is a thick muscle known as the cervix. As ovulation approaches, the same hormones that cause cervical fluid to be secreted also cause changes in the position, texture, and opening of the cervix.

During infertile periods (Phase 1 and 3), the cervix is low, firm and closed (during Phase 3, it is closed tightly). It is so low that it is fairly easy to reach for observation purposes. As fertility increases, the cervix rises in position, becomes softer, and starts to open. At peak fertility, the opening of the cervix is about 15 mm wide.

These changes make it easier for sperm to reach the ovum -- if the cervix didn't open, conception wouldn't take place. If the cervix didn't close tightly after ovulation, the uterus and fertilized egg could become infected. The cervix has to open somewhat at menstruation to allow the endometrium to be shed.

Its use in fertility awareness is primarily as an additional sign when temperature and cervical fluid do not define by themselves when post-ovulation infertility has begun.

Next: Putting it all Together