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Core Temperature Technology

When you’re trying to get pregnant, one simple thing you can do to help is to measure your core temperature, specifically what’s known in fertility circles as your BBT, your Basal Body Temperature. This is the low, minimum temperature your body cools to during a period of rest or deep sleep, when your heart rate is slower. If you measure this minimum temperature every day throughout your menstrual cycle, you’ll notice that it doesn’t remain constant: your minimum temperature varies, from day to day. If you measure it for multiple cycles, you’ll see how a specific pattern of changes coincides with when you ovulate, and so you can use it to give yourself warning and ensure you’re trying to conceive within your ‘fertile window’: those few days in each cycle when active sperm have a chance to encounter and fertilise an egg.

It can be time consuming and difficult to measure and chart your temperature every day for an extended period of time. Fortunately, there are plenty of technological solutions that can help make this more means of identifying when you ovulate easier for you to use.


One of the most important bits of kit is of course your thermometer. Specialist BBT thermometers are available, but you need to be aware of what you need, as you can end up paying too much for features that don’t actually help. What you’re looking for is something that offers an accurate reading down to the tenths of a degree, with a clear display that highlights changes at that level.

One thing you need to bear in mind is where you’ll be taking your readings from. An oral reading (from the mouth) is easy but not as accurate as taking a vaginal reading, which is of course potentially less comfortable. Some BBT thermometers are designed to make this easier and less uncomfortable, so remember to bear this in mind.

Processing Data

Turning all these temperature readings into a result takes a lot of work – you need to record them, perhaps turn them into a graph, and look for the right pattern every month that tells you when you’re due to menstruate.

There are now lots of apps available that can bear the weight of this work, but the results are only as good as the method they use. Research the background of an app before you use it so you know it can make good on its claims of accuracy.


OvuSense combines the best of both worlds: our sensor measures your core temperature right through night, so you know you’re getting an accurate result from it, and then transfers that data to be processed by our clinically tested algorithm, to give you not just a notification if you’re ovulating that day, but a prediction of your next fertile window!