How do I Calculate a Fertility Cycle?

Calculating your fertility cycle, the month-long period when a female undergoes physical changes related to her ability to reproduce, involves several elements. Keeping track of your physical changes, temperature, moods, and menstruation are some ways to calculate this cycle. This can aid you in getting pregnant, avoiding pregnancy, treating premenstrual syndrome (PMS), or simply having a better understanding of how your body works and how it affects you.

Charting your menstrual cycle begins with keeping a calendar. The first day of your period counts as "Day 1," and it typically lasts from three to five days. A week from your period, your body will begin to emit hormones to prepare for the release of another egg. Your uterus will develop a lining of nutrient-rich blood, and your vaginal secretions will become more viscous. Around 14 days after your period starts, the egg will be released and your chances of getting pregnant will be the highest. If the egg is not fertilized within a week, the uterine lining will be shed and the cycle will start again.

The length of the days in the example above are a general "rule of thumb" for females with a 28-day fertility cycle. You may have a fertility cycle that is longer or shorter than 28 days. This does not mean your fertility cycle is "abnormal." Some women have shorter or longer cycles, or it may even vary from month to month. Fertility cycles can also be changed by birth control, stress, and many other factors.

Even with a calendar and several months' worth of charted periods, it can be difficult to pinpoint exactly when you're ovulating. Female humans, unlike many other animal species, do not have many visual markers to tell when they're ovulating. This does not mean it's impossible to get a general sense of when you're ovulating, however. Besides charting the days of your cycle, you can take stock of your moods and subtle physical changes.

Ovulating women have some physical sensations, like tender nipples. Their moods may also change. Another visual marker of ovulation is vaginal discharge. A healthy vagina will secrete clear lubrication, which is made up of plasma and mucus. As you near ovulation, the mucus will become more viscous and turn white.

Women who are trying to get pregnant often will check their temperature to try and pinpoint their time of ovulation more precisely. Once the egg is released into the uterus, a woman's temperature will rise slightly. This is called the "lumen cycle."