How to Find Your Conception Date
A conception date is very important in determining when to take a pregnancy test and also in figuring the baby's due date. However, figuring the conception date requires a bit more than sitting and trying to remember the actual moment of conception. There is actually a little math involved.
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Instructions
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Look on the calendar and locate the first day of your last period. If you do not have this recorded on a calendar, try to remember by associating it with certain events in your date book.
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Add 14 days to the first day of your last period. This will tell you the estimated date of conception. It may not be accurate because you could have conceived at any point during the 14 days of ovulation. In addition, menstrual cycles are not exact. The 14-day ovulation is based on an average 28-day menstrual cycle. Despite the lack of an exact date, this method is a good starting point to determine your conception date.
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Use the ultrasound aging date for the fetus. On the first ultrasound, the doctor will give you a date in weeks and days that is the estimated age of your baby. Take this age and subtract 14 days or two weeks. Take this new age and use it to count backward on a calendar to find the date of conception. For example an age of six weeks and 5 days requires you to subtract 14 days, arriving at 4 weeks, 5 days. Then count backward 4 weeks and 5 days on the calendar to find your approximate conception date.
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Use a conception calculator. Pregnancy websites have devised a program to determine the due date and conception date of a baby, using a date keyed in by the mother. This date is the first day of the last period.
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Tips & Warnings
The medical community has dubbed the 28-day menstrual cycle as the norm for women. The woman is expected to ovulate 14 days prior to the period. The first date of your last period is therefore the end of your ovulation.
The calculations ask you to add 14 days to the first day of your last period because that 14th day is the first day that you could have possibly conceived.
