Ovulation Home Testing Kits

Published: March 09, 2023
Barbara Young
By Barbara Young, PharmD

Are you trying to become pregnant?  Ovulation home tests may help to increase the chance of getting pregnant by determining the best time in your menstrual cycle to have sex.

How do ovulation home tests work?
Ovulation home tests measure the change in hormone levels that occur during the process of ovulation. Several hormones are involved in this process, including luteinizing hormone (LH). LH helps the egg mature; later a rise in this hormone triggers the release of the egg. The LH levels can be measured from a sample of your urine.

How long after a positive ovulation test are you fertile?
A positive test will occur along with the increase in luteinizing hormone. This is generally around 24-36 hours before you release an egg.

The time of fertility begins approximately 3 to 5 days (sperm lifespan) before ovulation until 1 to 2 days after ovulation (egg lifespan).

When should I use an ovulation predictor kit?
In general, you should begin testing 3 to 5 days before the expected date of ovulation. The specific time of month to start testing depends on the length of your menstrual cycle. For example, if your normal cycle is 28 days, you'll need to begin testing on day 11 (the 11th day after you started your period). If you have a longer or shorter cycle interval than 28 days, talk to your health care provider about the timing of the test.

What test kit should I use?
Test kits are available from your pharmacy. There are many types of kits available in a range of prices. Some may include digital monitors or app-based programs. Ask your pharmacist for assistance in picking out the right test kit for your needs.

Be sure to read the instructions carefully and completely before you begin to use the test.

What else should I know about using an ovulation predictor kit?

  • Experts suggest testing in the morning to give you the best result.
  • Do not drink large amounts of fluids before using the test as it will dilute the amount of hormone(s) in your urine.
  • Some medications can affect LH levels. The medication, clomiphene citrate (Clomid), which is used to trigger ovulation, can increase LH levels. Estrogens, progesterone, and testosterone can decrease LH levels.
  • You may miss the hormone surge if you miss a day of testing. You may also not be able to detect a surge if you have an irregular menstrual cycle.
  • Talk to your provider if you are unable to detect a surge or do not become pregnant after using the kit for several months.
  • You should not use these tests to help prevent pregnancy, because it is not reliable for that purpose.

How well do ovulation predictor kits work?
Most kits are estimated to be 97% accurate at predicting an LH surge. However, they are less accurate in women who are menopausal, recently been pregnant, or who have impaired liver or kidney disease or polycystic ovary disease. It is important to read and follow all instructions carefully to get the most accurate results.

It is important to read and follow all instructions carefully to get the most accurate results. Ask your pharmacist for help in selecting a kit or if you have any questions about using it properly.

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