What is “Day One” of my cycle and why is it important to know when it is??

The first day of your period is easy to recognize – even if it is very light, so this is the day doctors calls  day one of your cycle.

By keeping a note of this, you can begin to keep a record of the length of your cycle, as although most women’s will be around 28 days long, some will vary by as much as three or four days either way or more – this is completely normal.

So, assuming your cycle is 28 days, you count from Day One and then when you start your next period, you begin again at Day One.

When will I ovulate (release an egg)?

You are at your most fertile just before and just after you ovulate. You can work out when you will be most fertile by deducting 14 and then 16 days from the date of your next period – these couple of days is when you’re most likely to get pregnant. This is approximate and may not be the same for every woman.

You can visit our ovulation calendar and start to plot your periods. Try this for a couple of months so you can see what your own personal pattern is and then work out when you are most likely to ovulate. You’ll know that’s the best time to try for a baby next month!

Note that these calculations may not be accurate if your ovulation cycle is less than 21 days long or more than 35 days, or if your menstrual cycle is irregular from month to month. Please consult your doctor for more detailed information on ovulation and the most fertile time for you if you are trying for a baby.