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BBT and Ovulation

When you’re trying to conceive, ovulation is one of the biggest events on your calendar. It’s when your ovaries release an egg, and it’s only around this time that you can get pregnant – the lifespan of the egg itself and sperm allow for a window of around five days before and one day after ovulation to successfully conceive.

One of the biggest challenges as you try to get pregnant is pinning down the day in each cycle when you ovulate. Even if you have a very regular cycle, identifying that key date specifically enough can be tricky. If you have cycles that are naturally longer or disrupted by stress it gets harder, and if you’re living with a condition like polycystic ovary syndrome, that can cause serious disruption to your monthly cycle, or cause you to skip ovulation all together it becomes both difficult and vital to find the day you to ovulate to give you a better chance to conceive a child.


One of the best clues you have – especially if you’re trying to get pregnant with PCOS – is your BBT, your basal body temperature. If you can measure it and understand what it’s telling you, you can predict when you’re going to ovulate and make sure you’re trying to get pregnant at the time you have the best chance to succeed.

Accurate Readings

The key is to get your data at the right time. If you take your temperature when you’re being active, then the subtle peaks and troughs that indicate when or if you’re ovulating will be drowned out. It doesn’t take much: simply being awake and active raises your body temperature significantly enough to swamp this vital information.

Your basal body temperature is the low your core temperature drops to as you rest overnight, so it’s important to measure it first thing in the morning, as soon as you awake and before you’ve got out of bed.

Even this can give you flawed readings so you may need to look for a better solution.


Our solution combines overnight monitoring of your temperature with a sensor (to monitor the true fluctuations of progesterone throughout your cycle) with the computing power of an app to get a truly accurate reading. OvuSense’s algorithm gets to know you as it gathers data and can give you two predictions: at the beginning of your cycle it will tell you the eight day window within which you’ll be most fertile, and follow this up with a notification 24 hours before you’re due to ovulate, to cue you up at the most important time.

Find out more about core temperature technology and fertility here