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How do I calculate my fertile window?

2 fertility expert(s) answered this question

How do you calculate your fertile days?

Knowing exact dates of the menstrual cycle for longer periods of time is essential to establish fertile days. Ovulation usually happens about 14 days before the period, however this is to be determined precisely after knowing the length of the cycle. Many patients are only vaguely aware of the so-called ‘window of implantation’ and how it correlates with IVF treatments. It is, however, a very important piece of the overall puzzle. What is it exactly? What is it determined by?

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Answer from the fertility expert:
Christos Kleanthis, Obstetrician and Reproductive Gynecologist

We know that sperm survives for 4 to 5 days in the genital tract and on the other hand egg survives only for 24 hours so the fertile window would be 4 to 5 days leading to the day of ovulation and only 24 hours after ovulation has taken place.

Answer from the fertility expert:
Leo Martinez, Chief Scientific Officer, Pearl Fertility by Colorimetrix GmbH

How do you calculate the fertile window? Fertile window is pretty much fixed around the time of ovulation so once you have found out about ovulation or estimation of ovulation, then you will know when your fertile days are: 3 to 4 days before .
You don’t have to worry about that. In the Pearl Fertility App which is the one we use to digitize these hormones’ tests we also do calculations. If you only have the periods information, you can calculate the fertile window and estimate your ovulation – it does all the information regarding cycle lengths, last 3 cycles – it does all the calculation dates for you and of course if you include the ovulation test it will show you with precision exactly when your fertile days are. The best way is to use the tracker and it will help you with calculation. Of course you can also do it manually if you can identify the ovulation very accurately by knowing that this is the 2nd, 3rd, 4th and 5th day before the ovulation.

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