Ovulation predictors are urine tests that tell you when your ovaries are about to release an egg. This can help you time intercourse to increase the likelihood that you will become pregnant. Ovulation predictors test the amount of luteinizing hormone (LH) in the urine.
The Monthly Hormone Cycle
Ovulation is a complex, delicately balanced process that requires several different hormones. The release of these hormones relies on feedback mechanisms. This means that the rise or fall of one hormone triggers the release of another hormone.
During your period, the level of estrogen in your system drops. This stimulates the hypothalamus in the brain to release GnRH, or gonadotropin-releasing hormone. GnRH stimulates the pituitary gland to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone). Luteinizing hormone triggers ovulation. Fourteen to 48 hours before the egg is released from the ovary, LH can be detected in the urine.
Ovulation Predictor
Ovulation predictors usually come with five to seven sticks. A chemical on the sticks binds with the LH present in your urine. The LH triggers either a color change or a plus sign to appear, depending on the brand of ovulation predictor you are using. The more LH that is present in the urine, the darker the color change will be.
You should test your first morning urine for five to seven days. You can either urinate directly on the sticks, or place the stick in urine you have collected in a clean container. You should start testing 17 days before your period is due. If your period starts every 28 days, you should begin testing your urine the eleventh day after your period starts. You can expect to ovulate in the next 24 to 36 hours after you get a positive result.
Home Fertility Monitors
Home fertility monitors are another option for predicting ovulation. These are electronic devices for predicting ovulation. Some home fertility monitors also test for LH in urine, while others predict ovulation based on basal body temperature or electrolytes in saliva.
Medications and Ovulation Predictors
Some medications, like estrogen, progesterone and testosterone, can decrease the amount of LH. These medications are found in birth control pills and drugs used for hormone replacement therapy. The fertility drug clomiphene increases the amount of LH. If you are taking clomiphene, wait three days after stopping the drug before testing your urine.
References
- Medline Plus: LH Urine Test
- American Family Physician Journal: Infertility
- Clinical Pharmacy and Therapeutics; Eric T. Herfindal, Dick R. Gourley, and Linda Lloyd Hart; 1992
