The conception is the moment that marks the beginning of the pregnancy and happens when the sperm fertilizes the ovum. Since it is a rather difficult time to calculate, the outcome of the conception date is generally given in a 10-day interval rather than a specific day, since it is in this period that the fertilization of the ovum must have occurred.
There are two main ways to calculate the period of conception:
1. Calculate through last menstruation
The conception can usually happen about 11 to 21 days after the first day of menstruation. Thus, knowing the first day of the last menstruation, the woman can estimate a period of 10 days in which conception may have occurred. Just add 11 and 21 days to the first day of last menstruation.
For example, if the last menstruation appeared on March 5, it means that the conception should have happened between the days 16 and 26 of March.
2. Calculate by estimated delivery date
This technique is similar to that of calculus through the date of last menstruation and is used, especially, by women who do not remember when it was the first day of last menstruation. Thus, through the date estimated by the doctor for childbirth it is possible to find out when it might have been the first day of last menstruation and then calculate the time interval for conception.
The doctor usually estimates the birth for 40 weeks after the first day of last menstruation, so if you withdraw those 40 weeks at the time of delivery, you will have the date of the first day of the last menstrual period before of pregnancy. With this information, it is then possible to calculate the period of 10 days for conception, adding 11 to 21 days to that date.
For example, in the case of a woman with a scheduled delivery date of November 10, 40 weeks should be withdrawn to discover the possible first day of the last menstrual period, which in this case will be 3 February. To this day, we must now join the 11 and 21 days to discover the 10-day conception interval, which should have been between the 14th and 24th of February.
