Charting Your Basal Body Temperature, Cervical Mucus and Cervical Position

The fertility awareness method (FAM) is a form of natural family planning that uses a combination of several separate methods - usually calendar charting, basal body temperature (BBT), cervical mucus, and cervical observation - to predict when a woman will ovulate.

The fertility awareness method helps women identify and predict ovulation so they can time their reproductive efforts to coincide with their most fertile days, thereby increasing the likelihood of conceiving. In general, a woman is able to get pregnant for about 5 to 7 days each month. Sperm can live inside a woman's body for 3 to 5 days after intercourse; but after ovulation, an egg is viable for just 24 to 48 hours. You are more likely to conceive if intercourse occurs from 3 days before ovulation until 2 to 3 days after ovulation.

Basal Body Temperature

Monitoring your basal body temperature can help you identify the change in temperature that occurs just before and after ovulation. After charting a few cycles, you will be able to distinguish a pattern in your temperature and anticipate ovulation.

Take your basal temperature orally every morning before you do anything, even get out of bed (even the slightest activity can elevate your temperature), and record it on your fertility tracking calendar. Use a basal thermometer instead of a conventional fever thermometer; your body temperature will only rise between 0.4 and 1 degree F when you ovulate and a basal thermometer is more sensitive to small changes in your temperature. As you get closer to ovulation, you may notice a slight drop in temperature followed by a sharp increase, indicating that ovulation has just occurred. The temperature spike occurs within 12 hours of ovulation and it will remain elevated until your next menstrual period begins. Your fertile days are just before the temperature spike, and for the three days following.

Cervical Mucus

The consistency of your cervical mucus changes during your menstrual cycle. In an average cycle, there are three to four dry days after a five-day menstrual flow. After the dry days, the mucus wetness increases daily, lasting approximately nine days until it becomes abundant, slippery, clear, and very stretchy, similar to egg whites. Ovulation occurs within two days of when your mucus becomes clearest, slippery, and most stretchy.

To monitor your cervical mucus, collect it from the vaginal opening every day with your (clean) fingers by wiping them from front to back, or examine the mucus that collects on your underwear. Record the consistency, color and feel daily to increase your awareness of your fertile period.

Cervical Position

The position of a woman's cervix changes over the course of her menstrual cycle. During menstruation and for the first few days after, the cervix is fairly low and firm like the tip of your nose. As ovulation nears, the cervix begins to move up, becoming more soft, wet, and open; during ovulation, the cervix is at its highest and most open to allow sperm through; and after ovulation, the cervix returns to the firm, low, and closed position.

To observe changes in your cervical position, insert your (clean) middle finger into your vagina and feel your cervix for softness, height, opening, and wetness. A plastic speculum can be helpful in the beginning while you are getting used to finding and feeling your cervix. Check your cervix about the same time of day and in the same position (squatting, sitting on the toilet, or with one leg raised). Record the position and quality of your cervix on your chart.

Charting Tips

Here are a list of descriptions and abbreviations you can use to chart your cycles. Using these terms will help you to become familiar with your body and the menstrual cycle signs it provides to identify your most fertile days. When describing the cervical mucus textures you will likely use one word from each category (consistency, color and feel) in order to completely pinpoint how near or far your ovulation is.