How to Calculate Ovulation Periods

The time period surrounding ovulation is the most fertile time in a woman’s menstrual cycle. Knowing when this time will arrive is an important step for anyone trying to achieve or prevent a pregnancy. Successfully predicting ovulation requires that you take the time to get to know your body and study your cycles. There are four main methods of ovulation prediction. The best results are achieved when more than one method is used over a period of several months.

Things You'll Need

• Basal thermometer
• Ovulation predictor kit

Instructions

1. Keep a calendar. Circle the first day of her period, which is when a woman’s cycle begins. Repeat this process each month. Once the second cycle has begun, count backwards from the second circle 18 days and put an “x” through that day. The “x” marks the first day you may have ovulated.

2. Take your temperature. Use a basal thermometer to take your temperature orally each morning before you get out of bed. Record your basal temperature each day. Use a chart to make it easier to spot patterns. You will see at .5 to 1.6 rise in your basal temperature after you have ovulated. The temperature will remain elevated until the start of your next period.

3. Check your cervical fluid, as cervical fluid, or vaginal discharge, stretches more than normal and resembles egg whites near ovulation. Put some of the fluid between your thumb and index finger. If you can stretch your fingers without breaking the string of fluid, this is most likely the type of fluid that indicates ovulation. The 12 to 24 hours during which you find this type of fluid is usually your most fertile time.

4. Get an ovulation predictor kit. There are two types of ovulation predictor kits, but both test urine for the luteinizing hormone (LH), which surges prior to ovulation. Urinate directly onto the test stick or dip the test strip in a collected urine sample. Check the control window to ensure the test is working. Wait the amount of time indicated on the directions and compare results with sample provided on the package insert. A positive result indicates you will ovulate within the next 36 hours.

Tips & Warnings

• According to the American Pregnancy Association, women generally ovulate 12 to 18 days before the start of their menstrual period. Keeping a calendar for several months will help you find the pattern in your cycles.

• If you menstruate regularly, you will notice regularity to your ovulation as well.

• Follow the directions on your ovulation predictor kit carefully, as they vary by brand.

• An extremely light color band on an ovulation predictor kit does not indicate ovulation. According to Ovulation Calculator, there is always a small amount of LH in your body.

References

• Ovulation Calculator: Using a Fertility Calendar to Predict Ovulation
• American Pregnancy Association: Ovulation Frequently Asked Questions
• Women's Health: Basal Body Temperature Chart

Resources

• Read this Article in Spanish