Estimated date of delivery

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Estimated date of delivery (EDD), also known as the due date, is a key concept in obstetrics used to predict the approximate date when a pregnant woman is expected to give birth. The EDD is typically calculated based on the last menstrual period (LMP) or through an ultrasound scan.

Calculation Methods

Last Menstrual Period (LMP)

The most common method to estimate the due date is by using the first day of the woman's last menstrual period. This method assumes a 28-day menstrual cycle with ovulation occurring on the 14th day. The formula used is known as Naegele's rule, which adds 280 days (40 weeks) to the first day of the LMP.

Ultrasound

An ultrasound scan can provide a more accurate EDD, especially if performed in the first trimester. The crown-rump length (CRL) measurement is used to estimate the gestational age and, consequently, the due date.

Other Methods

Other methods include the use of pregnancy wheels and online calculators, which incorporate various factors to estimate the due date.

Importance of EDD

The EDD is crucial for monitoring the progress of the pregnancy and planning for the delivery. It helps in scheduling prenatal care visits, conducting necessary tests, and preparing for potential complications.

Factors Affecting EDD Accuracy

Several factors can affect the accuracy of the EDD, including:

• Irregular menstrual cycles
• Late ovulation
• Inaccurate recall of the LMP
• Variations in fetal growth

Related Pages

• Pregnancy
• Prenatal care
• Obstetrics
• Ultrasound
• Gestational age
• Naegele's rule

Categories

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