Determining Ovulation Timing
Ovulation Predictor Kits: These kits (available at your local drugstore without a prescription) detect levels of a substance called Luteinizing Hormone in urine. This hormone has an increase, known as a 'surge,' about 24 hours before ovulation. These kits are most useful for women who have regular 25-35 day menstrual cycles (meaning there are 25 to 35 days between the beginning of one period to the beginning of the next). It is good to combine the use of OPK's with other methods of detecting ovulation (listed below) in order to get a better idea of when to start testing the urine with the store-bought kit. OPK's are a good way to detect ovulation before it happens, versus other methods that can only detect it after the important event.
Generally, the predicted date of ovulation can be found using the following equation:
Cycle Length (i.e. number of days between start of one period to start of next) - 18.
The resultant number is the number of days from the first day of your period until your ovulation begins. For example, if there are 30 days from the start of one period to the next: 30-18 = 12. Thus, if menses begins on September 3, add 12 days to get the approximate day of ovulation. September 3 + 12 days = September 15. Ovulation will occur on/about September 15. Thus, it may be a good idea to use the OPK on Sept. 14, 15, and 16.
It is important to carefully follow the directions on the package of the OPK, as there are various formulations on the market.
Basal Body Temperature (BBT) Monitoring: This method of detecting ovulation takes advantage of the rise in body temperature that occurs after a woman ovulates (due to hormones that are released). To monitor basal body temperature, you should take your temperature with a mercury thermometer (electric thermometers are not sensitive enough) before getting out of bed in the morning. Start monitoring the first day of the period; record the temperature each day. Your temperature will rise about 0.5 degrees Fahrenheit one to two days after the surge in Luteinizing Hormone, and this will tell you you when you have ovulated. Although ovulation has already occurred, it is still useful to time sexual intercourse to correspond with the rise in basal body temperature. However, this method is not very effective alone. Combining this technique with other methods can be very helpful in identifying your pattern of cycle length and ovulation.
Cervical Mucous Monitoring: This method of detecting ovulation monitors the change in consistency of cervical mucous that corresponds with ovulation. Monitoring involves collecting cervical mucous/discharge at different times of the month and recording the consistency. In order to retrieve the cervical mucous, you should insert a finger into the vagina, circle around the cervix/vagina, and then hook the finger to gather the mucous. To evaluate the consistency of the mucous, put it between two fingers (usually the thumb and index finger). Stretch your fingers apart; mucous during ovulation will be clear, slippery, and stretchable (usually stretching an inch or more before clinging to one of the spread fingers). Some describe the consistency as that of a raw egg white. The cervical mucous will likely be cloudy before and after ovulation. In order to have the best chance of conceiving, sexual intercourse should be timed to correspond with the time that cervical mucous is clear, slippery, and stretchable. In older women the vagina tends to be dryer and this method may be more difficult.