Luteinizing hormone in elevated quantities causes ovulation. During the menstrual cycle only a small amount of LH is made, but in the middle of the cycle LH briefly and dramatically increases. This increase is called the “LH surge” and precedes ovulation. Conception is most likely to occur within thirty-six hours following the LH surge. The LH Ovulation Test is specifically designed to detect your LH surge – the time when you are likely to ovulate. To determine when to start testing for ovulation, follow the instructions below:
1. Determine the length of the menstrual cycle. The length of the menstrual cycle is the number of days from the first day of menstrual bleeding to the day before bleeding begins on the next period.
2. Determine the usual length of the menstrual cycle over the last few months. Then, refer to the Ovulation Calendar Cycle Chart below to determine on which day of the menstrual cycle to begin testing. If your cycle is less than twenty-one days or greater than forty days, consult a physician.
|Your Cycle Length
||Day to Begin Testing|
|21 days||Day 5|
|22 days||Day 6|
|23 days||Day 7|
|24 days||Day 8|
|25 days||Day 9|
|26 days||Day 10|
|27 days||Day 11|
|28 days||Day 12|
|29 days||Day 13|
|30 days||Day 14|
|31 days||Day 15|
|32 days||Day 16|
|33 days||Day 17|
|34 days||Day 18|
|35 days||Day 19|
|36 days||Day 20|
|37 days||Day 21|
|38 days||Day 22|
|39 days||Day 23|
- Fertility Testing Guide: Ovulation & Pregnancy
- Ovulation and Pregnancy Test FAQ
- Ovulation Test FAQs
- Fertility & Ovulation Predictor Tests
- How do Ovulation Tests predict fertility?
- How do I interpret ovulation test results?
- How do I determine when to begin testing for ovulation?
- Help using ovulation tests
- How to use your basal thermometer
- Ovulation Microscopes: Instructions & FAQ
- Predicting Ovulation with the ClearBlue Fertility Monitor
- Fertility Charting with a Saliva Ovulation Microscope
- Detecting your “Estrogen Surge” with the OvaCue Fertility Monitor
- A Game Plan for Getting Pregnant with an Irregular Cycle!