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Charting Your Menstrual Cycle

By OBOS Anatomy & Menstruation Contributors |

You may find it helpful to keep a menstrual calendar or a special fertility awareness chart. By doing so, you can get to know your body, learn what is normal for you, and become an advocate for and authority on your own health.

Any print or online calendar or diary can be used to chart when you bleed, whether and when you have vaginal secretions, and whether you have a range of physical or emotional experiences (including pain or cramps; heavier or lighter flow; change in sexual desire, energy level or mood; swollen or tender breasts; or any difference in your general physical health). You can find menstrual charts at the Taking Care of Your Fertility website.

Fertility Awareness Method

One way of charting your menstrual cycles is to use the fertility awareness method (FAM). In addition to being a good tool to assess your gynecological health, FAM is a scientifically validated method of natural birth control and pregnancy achievement. It is based on observing and charting body signs such as changes in the cervical fluid and in the color, size and shape of the cervix that reflect whether a woman is fertile on any given day.

FAM is based on the following scientific principles:

  • Your menstrual cycle can basically be divided into three phases: the preovulatory infertile phase, the fertile phase, and the postovulatory infertile phase. You can determine which phase you are in by observing the three primary fertility signs: early morning (waking, or basal body) temperature, cervical fluid, and cervical position.
  • The menstrual cycle is under the direct influence of estrogen and progesterone, and the body provides daily signs about the status of these hormones. Estrogen dominates the first part of the cycle; progesterone dominates the latter. Another hormone, called luteinizing hormone (LH), is the catalyst that propels the ovary to release the egg. LH is the hormone measured in ovulation predictor kits.
  • Ovulation (the release of an egg) occurs once per cycle. During ovulation, one or more eggs are released. An egg can survive for 12-24 hours. If a second egg is released in one cycle (as in the case of fraternal twins), it will be released within 24 hours of the first.
  • The time from a woman’s period until ovulation varies, but it is often about two weeks.
  • Sperm can live in fertile-quality cervical fluid for up to five days, though typically they live only about two days.

Primary Fertility Signs

Waking or Basal Body Temperature (BBT)

Before ovulation, early morning temperatures typically range from about 97 degrees to 97.5 degrees Fahrenheit (36.11 to 36.38 degrees Celsius), and after ovulation, they usually rise to about 97.6 degrees to 98.6 degrees Fahrenheit (36.44 to 37 Celsius). It’s helpful to use a special basal or digital thermometer to get readings that are precise enough to track such small changes.

After ovulation, your temperature usually remains elevated until your next period, about two weeks later. But if you become pregnant, it remains high for more than 18 days.

The important concept to understand is your pattern of low and high temperatures. Your temperatures before ovulation fluctuate in a low range, and the temperatures after ovulation fluctuate in a higher range. The trick is to see the whole and not to focus so much on the day-to-day changes. Temperatures typically rise within a day or so after ovulation, indicating that ovulation has already occurred.

A sustained rise in waking temperature almost always indicates that ovulation has occurred. It does not reveal impending ovulation, though, as do the other two fertility signs (cervical fluid and cervical position). After charting a few cycles, if your cycles are consistent, you should be able to see how these three signs interact.

It is often believed that most women ovulate at the lowest point of the temperature graph, but this is true for only a minority of women. It’s more common for ovulation to occur the day before the temperature rises.

Factors that may disrupt your morning temperature:

  • Fever
  • Alcohol consumption the night before
  • Fewer than three consecutive hours of sleep before taking temperature
  • Eating or drinking before taking an oral temperature
  • Taking temperature at a substantially different time than usual
  • Heating your body, as with an electric blanket
  • Thyroid conditions
Cervical Fluid

Cervical fluid is the secretion produced around ovulation that allows sperm to reach the egg. In essence, fertile cervical fluid functions like seminal fluid: It provides an alkaline medium to protect the sperm in an otherwise acidic vagina.

In addition, it provides nourishment for the sperm, acts as a filtering mechanism, and functions as a medium in which to move. Cervical fluid also capacitates the sperm; this process removes the tip of the head, preparing it to fertilize the egg.

After your period and directly under the influence of rising estrogen, your cervical fluid typically starts to become wetter as you approach ovulation. After your period ends, you may have several days of nothing, followed by cervical fluid that evolves from sticky to creamy and finally to clear, slippery, and stretchy (also known as spinnbarkeit), similar to raw egg white. The most noticeable feature of this fertile cervical fluid is its lubricating quality.

After estrogen has peaked and dropped, the cervical fluid abruptly dries, often within a few hours. This is due to the surge of progesterone following ovulation. The absence of wet cervical fluid usually lasts the duration of the cycle.

A trick to help you identify the quality of the cervical fluid at your vaginal opening is to notice what it feels like to run a tissue (or your finger) across your vaginal lips. Does it feel dry? Is it smooth? Does it glide across? When you are dry, the tissue won’t pass smoothly across your vaginal lips. But as you approach ovulation, your cervical fluid gets progressively wetter, and the tissue or your finger should glide easily.

As with temperature, certain factors may mask or interfere with cervical fluid:

  • Vaginal infection
  • Semen (from recent sexual intercourse)
  • Arousal fluid
  • Spermicides and lubricants
  • Antihistamines (which can dry out or decrease fluid)
  • Guaifenesin (an expectorant, which can increase fluid)

In addition, if you have recently stopped taking birth control pills, you may notice one of two very different patterns: Either you may not produce much cervical fluid at all, or you may tend to have what appears to be continuous creamy cervical fluid for several months.

Cervical Position
In addition to emitting cervical fluid, your cervix goes through changes throughout your cycle. These changes can sometimes be felt by inserting a clean finger into your vagina (your middle finger is usually easiest, since it’s the longest).

The cervix is normally firm, like the tip of your nose, and becomes soft and rather mushy, like your lips, as you approach ovulation. In addition, it is normally fairly low and closed, and rises and opens only in response to the high levels of estrogen around ovulation. The angle of the cervix also changes around ovulation, becoming straighter when estrogen levels are high.

Secondary Fertility Signs

Secondary fertility signs around ovulation may include pain or achiness near an ovary, increased sexual feelings, and abdominal bloating. Secondary fertility signs do not occur in everyone, and if they do occur, they may not repeat in every cycle. Still, these signs, when apparent, can offer additional information to help identify fertile and infertile phases.

For more information on using the Fertility Awareness Method to prevent pregnancy or to conceive, see the book and website Taking Charge Of Your Fertility.