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Your Basal Body Temperature and Ovulation

When you decide the time is right for you to try and get pregnant, it suddenly becomes important to identify, track and predict when you ovulate. Ovulation is what makes you fertile: you can’t become pregnant unless there’s a viable egg for sperm to fertilise.

If you know when you ovulate, you can identify your fertile window – the days when you stand the best chance of conceiving naturally. This is a six day period of time, starting five days before you ovulate (because sperm can survive up to five days in a woman’s body) and ending the day after (because that egg remains viable for no more than twenty-four hours). The further in advance you can predict when you will ovulate, the more of your fertile window you will have access to.

One of the most widely recommended methods for identifying and predicting ovulation is tracking your basal body temperature. This is the low temperature your body drops to during an extended rest – like an overnight sleep. If you measure this temperature regularly, you’ll see that it changes by small amounts. These changes are caused by different processes inside your body – including ovulation. In the three days running up to ovulation, some women see a dip their BBT immediately before they ovulate. All women should find a rise in their average temperature, which means it’s higher right up until their period begins. If you can identify this pattern, you can start to pinpoint what day you ovulate in your period and therefore predict it in the future.

Unfortunately this means there are some significant drawbacks to this method. If you have an irregular cycle, for example, then you can’t use the information from one cycle to guess at when you’ll ovulate in the next. There are also lots of different things that can affect your temperature, from illness and diet to simply getting a poor night of sleep, any of which could mean that your data is thrown off and you’re wrong about when you ovulate.

OvuSense uses a different approach, that uses your core temperature (which is less affected by environmental variables) to track your progesterone levels directly. Our clinically tested algorithm is able to use this data to predict when you will next ovulate, and therefore when you be fertile, starting with only a few days of data. It can help you pinpoint your fertile window even with irregular cycles and conditions like PCOS, making OvuSense a real advantage when you are trying to conceive.