The estimated date of confinement is the date when a pregnant woman is expected to give birth to a child. Usually, an exact date at which an infant is born is calculated from the time of the last menstrual period of a woman. It is common to give birth between thirty-eight and forty-second weeks of pregnancy.


Confinement as an expression refers to medieval times when during a specific time, women from the upper-class had to be confined in their homes with servants to ensure that a baby would not be harmed. Only female members of the family were allowed to visit a pregnant woman during that time. Nowadays, the term estimated date of confinement is sometimes changed to the expected date of delivery (EDD), which means the same.

The EDD can be calculated manually by using two ways. The first way to estimate the due date is to use Naegele’s Rule. A woman needs to add seven days to the first day of her last menstrual period (LMP) and subtract three months. The second way is to use a pregnancy wheel with a doctor, which also involves using the LMP date and a unique indicator on a wheel. The number of days from the first day of the last menstrual period to the estimated date of confinement is a gestational age, which shows the age of the pregnancy. The gestational age also indicates how far a woman is from having a baby. Typically, the period of full 40 weeks (or 280 days) from LMP defines the due date. To be more precise about the estimated time of confinement, researchers suggest using LMP date, early ultrasound, and known date of fertilization.