How to Calculate Ovulation

Finding out the regular schedule of your menstrual cycle will help if you are trying to have a baby. Once you know the regular number of days between periods, you can figure out your ovulation cycle. The ovulation period is when conception is most likely, and this is the best time to try for a baby; this occurs near the halfway point of your menstrual cycle. From there, you can figure out the projected due date should you get pregnant during that ovulation time.

To know the fertile days is ideal for women that want to get pregnant, because in those days you must have sexual relations, its better if you do it 2 or 3 days before ovulating and until 1 day after ovulating. It must be done this way because it has been proven that the sperm can live around 72 hours inside the uterus and the ovules only 24 hours. Now, every woman's dilemma is how to calculate the ovulating period. Usually, in general terms, to calculate that period we just have to subtract 15 days to the next date of our menstrual period. For example, if our next menstrual period will be the 25, the fertile days will be the ones from the 8 to 12 approximately. This example can be applied to regular menstrual cycles of 28 days.

By the contrary, if the cycles are short and last from 23 to 25 days, you will have to subtract 10 to 13 days to the next menstrual period. And in the case of long menstrual cycles, from 30 to 35 days, you will have to subtract 17 to 20 days to the next menstrual period.

For women who have a 28 to 32 day menstrual cycle, ovulation can take place between days 11 through 21. Remember this is just an average of days that ovulation could take place—every woman's cycle is different.

Instructions
1
Count and track the number of days in your menstrual cycle. Mark down the days on a calendar from the first day of your menstrual period -- the first day that menstrual bleeding occurs -- to the day before the next period begins.

2
Divide the number of days in the menstrual cycle by half. If the menstrual cycle is 28 days, this number (14) is the last day of your three-day ovulation period.

3
Subtract two days from the divided number if your cycle is fewer than 28 days to get the ovulation end date; round up if the cycle is longer. For cycles shorter than 26 days or longer than 30, add/subtract three days instead of two.

4
Count off the weeks from the last date of the ovulation period using your calendar. Mark down the date 38 weeks after the ovulation date to get the estimated due date should conception occur in the aforementioned period.

5
Count 10 weeks from the ovulation end date -- the most likely day of conception -- to get the end of what would be your first trimester. Count 26 weeks for the end of the second trimester.