How To Determine Your Due Date

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A new mother’s due date is always a topic of great interest for anyone expecting a baby. In order to calculate the day your baby is due, your doctor will start by asking you the date of your last menstrual period. The doctor will count forty weeks from the first day of your last period. The date that is forty weeks from the first day of your period is your due date.

The concept of a due date being calculated forty weeks from the first day of your last period is confusing for many women. A common question pregnant women ask is “How can you determine the due date from the first day of my last period if my partner and I did not have sex until a week or two after my period?” It is important to know that when doctors state that you have been pregnant for forty weeks, you actually really have not been pregnant for forty weeks but rather approximately only thirty eight weeks or possibly thirty eight weeks and a few days. Doctors cannot determine with exact preciseness the day that you conceived, but they do know with exact preciseness the first day of your last period. It is for this reason that the due date is calculated based on the first day of your last period.

Although your due date is forty weeks from the first day of your last period, it does not necessarily mean that you will be due exactly on that date but rather the date serves as a convenient reference point for when your pregnancy will be over.

In addition to calculating one’s due date forty weeks from the first day of your last period, ultrasounds are also used to determine one’s due date. The earlier an ultrasound is performed during pregnancy, the more accurate the ultrasound will be when predicting your due date. When measuring things very small such as the fetus, the range of error is usually very small. It is for this reason that an early ultra sound is the most accurate way to determine your due date. Many doctors will try to order an ultra sound during the early stages of pregnancy in order to accurately predict when your due date will be.

If you have any questions about your due date or due dates in general, please feel free to leave a comment and we will get back to you shortly.