Calculate age

Calculating gestational age and due date

Determining gestational age is one of the important issues that you should definitely know about because it helps you know when to do what tests and procedures and how long to wait for your baby to be born. We will talk about this later in this article. There are several methods for estimating gestational age.

The most common and easiest way is based on the LMP, or the first day of your last period. To calculate gestational age, you need to count the weeks from this date to today's date. This number corresponds to the number of weeks you are pregnant.

Calculating Gestational Age and Calculating Due Date

Your due date will be approximately 40 weeks after your LMP date. Add seven days to your LMP date, then count back three months and add one year.

((First day of last period + 7 days) – 3 months) + one year = due date

This calculation is not exact, as babies can be born between 37 and 42 weeks of pregnancy, but estimating the due date allows parents and their healthcare team to prepare for the birth.

What if I don't know the date of my last menstrual period?

If you're not sure when your last menstrual period was, or you have irregular cycles, the most accurate way to find out how many weeks pregnant you are is to have your obstetrician or gynecologist tell you your gestational age via ultrasound.

Ultrasound, doctor's examination and beta test are among the ways that can help you determine the age of pregnancy if you have not had regular menstruation.