Charting your basal body temperature (BBT) is a simple method of estimating the time of ovulation. It is not possible to pinpoint the time of ovulation exactly, but by carefully charting your BBT each day, you can estimate when you ovulate. If you are trying to become pregnant, it is important to know when you ovulate, because only during the short period of time surrounding ovulation can conception occur.

The basal temperature is lower than the normal 98.6°F. A woman's BBT is lower in the first part of her menstrual cycle, and after ovulation there is a rise of 0.4° to 0.6°F; the temperature remains elevated for the rest of the cycle. To increase your chances of becoming pregnant, you should have intercourse every other day for the 3 to 4 days before the estimated time of ovulation (or temperature rise) and the 2 to 3 days after.

There are three kinds of thermometers you can use to monitor your BBT:

• A special "basal" thermometer (labeled in 1-degree increments).

• A standard oral thermometer (labeled in 2-degree increments).

Since accuracy is important, basal and digital thermometers are better choices.

1. Take your temperature upon waking, at about the same time each day; after at least 3 hours of uninterrupted sleep; and before lifting your head off the pillow. If you forget to take your temperature and have already gotten up, do not take it. Write "missed" on that day.
2. Place the basal or standard oral thermometer under your tongue and leave it in place for at least 3 full minutes (your clinician may advise you to leave it in place for up to 5 minutes). For digital thermometers, follow the manufacturers' directions.
3. Record the reading on the graph by placing a dot at the proper location. If intercourse has taken place during the previous 24 hours, cross the dot (X). If you are using either a standard or a basal thermometer, be sure the thermometer and the graph are labeled in the same scale.
4. Write the month and day in the space provided.

5. The first day of menstrual flow is the start of a cycle (Day 1). For each day of flow, put a circle on the graph, starting at the left under the first day of the cycle.
6. The first day of your period is also the end of the previous cycle. Write "Period" on the first chart and begin a new chart with Day 1.

8. Some women have a little bit of pain low in the abdomen or notice a few drops of blood from the vagina (spotting) around the middle of their menstrual cycle. If this happens to you, put a P (for pain), an S (for spotting), or PS (if you have both) in the space labeled "Symptoms."

All this said, unless you have a religious reason for doing this so naturally, I recommend the use of ovulation predictors. They have become much simpler in recent years and the hormone surge that these predictors detect is present before ovulation. The temperature spike occurs after. So with your thermometer you are predicting a pattern in your body which may or may not be consistent from one month to another.

My advice to anyone who is trying to get pregnant is do it as rapidly as possible. If you just want to "see what happens", do that for three months. After that, it can get more serious. Once you are off the pill endometriosis that has been dormant can recur, ovulatory cysts can create pain and lead to surgery and occasionally menses are more regular coming of the pill and allow you to predict your ovulation approximately enough to use less of the predicting devices during your mid-cycle.

Also, heaven forbid there is a fertility problem, the predictor documents ovulation or anovulation better that the temperature chart and gives me some information to possibly start treatment on the first visit for infertility.

I am also not in favor of those high-dollar digital devices. A calendar, a pencil and some thought will accomplish the same thing. Just because it is $150 doesn’t give it special powers to get you pregnant.  

FRED CREUTZMANN, M.D. – CARROLLTON

972-384-7277 or www.DrCmd.com