What is gestational age?

Gestational age is the age of your unborn baby.

How is gestational age calculated?

The age of your baby and your due date is estimated to be 40 weeks from the day you started your last period. An early exam of your uterus and an early positive pregnancy test can help determine your baby’s age and due date.

Ultrasound can be used to confirm your baby’s age. An ultrasound uses sound waves to show pictures of your baby. Your baby can be measured with ultrasound as early as 5 or 6 weeks after your last menstrual period. This method is most accurate during the first half of pregnancy.

Why is it important to know the gestational age?

There are many reasons why it’s important to know your due date and how far along your pregnancy is. Some reasons are:

• At specific weeks of pregnancy, certain things are expected–for example, hearing the baby’s heartbeat for the first time (with a stethoscope) and feeling your baby move for the first time. If these things happen when expected, they can be a sign that your baby is doing well.
• Checking the growth of your baby can be done accurately only if your baby’s age is correctly known.
• Some tests should be done at certain times in the pregnancy.
• It’s very important to know your baby’s age if there are complications with the pregnancy and your baby needs to be delivered early.
• It’s important to know when your baby is overdue so the health of the baby can be watched more closely.