Ovulation: Understanding the Body's Fertility Signals

Getting pregnant shouldn’t be a scientific process.  But for many people, trying to pinpoint their most fertile days can go from a simple task to a feeling like it’s time to get out the chemistry set from middle school.  Because every person is different, so are the ovulation cycles between women.  No two are the same, and what is steady and reliable for one woman may be just an unpredictable for another.   Remember that when you are trying to conceive, it can take several months to chart your own personal cycle and then use that information to get pregnant—or avoid it, if necessary.

Ovulation is the body’s process of maturing and releasing an egg for fertilization.  When an egg is released during a monthly cycle it will either be fertilized by a sperm and result in a pregnancy, or left unfertilized, where it will be washed away with the lining of the uterus during a period, or menstrual cycle.  Learning to predict when an egg will be released is fairly simple through the use of an ovulation calendar, along with the close observation of other signals your body sends out.  An ovulation calendar helps you determine when you’re ovulating and track those days so that you can either engage in, or avoid sexual activity. 

Each month, a woman's ovaries receive hormonal signals to produce an egg. When that egg is mature, it breaks forth from the ovary and moves into the fallopian tubes which serve as a connection between the ovary and uterus—where the egg will implant if it becomes fertilized, and will grow until birth. Most eggs are fertilized high in the fallopian tubes, and the egg then travels down into the uterus to tap into the valuable blood supply that will be necessary to sustain the pregnancy.   If the egg isn’t fertilized, it will be passed out of your body along with the uterine lining during your menstrual period.

Knowing when you ovulate is the key to knowing the most likely time that you can get pregnant. A general rule of thumb is that ovulation will occur in the middle of your cycle—so if you have a space of thirty days between periods, you can estimate that you will ovulate somewhere around fifteen days from the first day of your last period.  Other ways of knowing that you are ovulating include an increase in your sex drive thanks to changing hormone levels, along with an increase in vaginal mucus production.

Of course, the length of the menstrual cycle varies from woman to woman. In general  though, the average length is 28 days. The menstrual cycle is counted from the day your period begins and you ovulate around day 14 in an average cycle. If your menstrual cycle is longer than 28 days, you typically ovulate about 14 days before the beginning of your period.

 Sperm can live in your fallopian tubes and uterus for up to five days, assuming normal conditions, and it can take this long for just one sperm to make it through the challenges of the female reproductive system and join with an egg.  This means that if you want to avoid pregnancy, you must abstain from unprotected intercourse beginning six days before you expect to ovulate.

To track your menstrual cycles it might be helpful to have a calendar. It’s also very helpful to have a thermometer to track your core body temperature, which can indicate when you are ovulating if you aren’t sure by other methods.

Take your temperature at the same time every day before getting out of bed and before having anything to eat or drink. Note your exact temperature; don’t round up or down. It’s also a good idea to track other symptoms as well, such as breast tenderness and/or changes in cervical mucus.  It can be very helpful to plot your temperature on a chart, or just write it on your calendar so you will be able to see when your temperature elevates. Don’t expect a big increase—sometimes temperature elevations are only minor—a couple of tenths of a degree—and you will need to chart your temperatures for several months before finding your personal pattern.

When you ovulate, your average basal body temperature will increase. You may also notice some increased breast tenderness around the time of ovulation. Your cervical mucus changes around the time of ovulation and becomes clear and somewhat stringy, much like egg whites. Your temperature will stay elevated for a period of about 12 days—though only a bit. If your temperature drops and you aren’t pregnant, you can expect your period to begin on time. If your temperature stays up and then increases slightly, there could be a chance that you’re pregnant.

By recording this information every day, you’ll eventually see a pattern start to emerge. It may be that your breasts become tender the day before you ovulate, or that you tend to ovulate more or less than 14 days before your period. You can then use this information to determine the best time to engage in sexual activity to maximize your chances of getting pregnant.