The actual pregnancy can be counted from the day of conception, but clinically not every woman can specify which day of conception, will cause the date of pregnancy calculation error, clinically is based on the first day of the last menstrual period to project the number of days of pregnancy.
Not every woman can determine their own specific time of conception, women often after many times of sexual intercourse before the success of the pregnancy, can not be sure which after the first time of sexual intercourse after the success of the pregnancy, according to the day of conception to count the actual time of pregnancy, will cause the date of pregnancy calculation error.
Clinically, it is based on the first day of the last menstrual period to calculate the number of days of pregnancy, most women can remember their last menstrual period, the first day of the last menstrual period to the date of the current pregnancy, out of the number of days of pregnancy, according to the first day of the last menstrual period, but also able to project the expected date of delivery time.
If you want to know how many days pregnant you are, you can also go to the hospital to have an ultrasound examination, and let the professional doctor judge according to the development of the fetus.