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How Accurate are Ovulation Tests?

If you’re trying to get pregnant, then you’ve likely looked at lots of different ways to predict when you’re going to ovulate. They all have different pros and cons: convenience, comfort, and expense but the most important thing you have to consider is accuracy. If the answers you’re getting aren’t accurate then all the time and effort you’ve put into tracking your ovulation will be going to waste, even if it’s cheap, convenient and comfortable.

Let’s put ovulation tests in the spotlight and see if they can really give you an accurate assessment of when you’re due to ovulate.

How Do They Work?

The first question we have to answer is how these tests actually work. The sort of ovulation test you can pick up in many pharmacies and supermarkets tests your urine, similar to a pregnancy test. When it detects elevated level of LH (the hormone that cues your ovaries to release an egg) it registers a positive result, letting you know ovulation is imminent.

Are They Accurate?

The most important thing to remember is that no ovulation predictor is 100% accurate, whatever technique it uses, and how accurate any particular one is varies significantly with the conditions it’s used under.

Under ideal circumstances, some of these testing kits promise up to 99% accuracy. But what are those circumstances?

Who Are They For?

Rather than offering bespoke results for each user, off the shelf ovulation tests are designed for the average woman. The average woman has no major health issues that might interfere with her fertility, the average mix of reproductive hormones, and isn’t taking any fertility drugs.

If you’re affected, or think you may be affected by any of these issues, a hormone based ovulation test will take a dramatic plunge in predictive power.

How Can it Go Wrong?

Low levels of LH might cause false negatives, while if you naturally produce lots of this hormone, you’ll find a positive result could start appear days too early or too late. As the object of the exercise is to identify with accuracy the precise date of your ovulation, this blurring of results makes the tests much less useful.

Taking fertility drugs causes spikes in the hormones the test measures so it could cause more false positives, and a condition like PCOS renders test like these near useless: they’re only meant for use around the middle of your cycle and with the extended and irregular menstrual cycles PCOS causes, identifying this window is a challenge in itself.


Fortunately, there are alternatives to hormone-based ovulation prediction kits. Measuring your basal body temperature tracks the body’s response to ovulation more directly than testing hormones, and this is the method OvuSense uses, with a sophisticated sensor, and the convenience and calculating power of an app to deliver a prediction of when you’re due to ovulate at the beginning of your cycle, and in detail 24 hours before, to give you the chance of conceiving successfully.

Find out more about core temperature technology and fertility here