Can an estimated date of conception be wrong?

Yes, an estimated date of conception (EDC) can be wrong. There are a number of factors that can affect the accuracy of an EDC, including:

* The date of the last menstrual period (LMP): This is the most important factor in determining an EDC. However, it can be difficult to remember exactly when your last period started, especially if you have irregular cycles.

* The length of your menstrual cycle: The average menstrual cycle is 28 days, but it can vary from 21 to 35 days. If your cycle is shorter or longer than average, this can affect your EDC.

* The time of ovulation: Ovulation usually occurs 14 days before the start of your next period. However, it can occur earlier or later, depending on your individual cycle.

* The accuracy of the ultrasound: An ultrasound can be used to estimate the age of a fetus. However, ultrasounds can also be inaccurate, especially early in pregnancy.

In general, an EDC is considered to be accurate within plus or minus 5 days. However, in some cases, it can be off by up to 10 days. If you are concerned about the accuracy of your EDC, talk to your doctor.