How Do I Know How Many Weeks Pregnant I Am?

The most common method to calculate gestational age is using pregnancy calculators, which rely on the date of the last menstrual period (LMP) – the first day of the last period. For example, if five weeks have passed since your last period, and you are pregnant, you would be considered five weeks pregnant.

This method has been designed for women with regular 28-day cycles. Since a normal menstrual cycle can vary from 21 to 35 days, pregnancy calculators may not always provide an exact estimate. For this reason, this calculation method is usually confirmed by an ultrasound performed between weeks 7 and 13, measuring the crown-rump length (CRL) of the embryo. This combined with the LMP provides a more accurate estimate of gestational age. Throughout pregnancy, additional fetal measurements, such as biparietal diameter, abdominal circumference, and femur length, help confirm gestational age and monitor fetal development.

There are many applications available that may help calculate your pregnancy weeks, estimate your due date, and track your baby's development.