How Do I Determine My Baby’s Due Date?

First finding out when or how soon you’ll be receiving your new bundle of joy can be one of the most exciting and anxiety packed times of your life, let alone one of the most anticipated bits of information concerning your entire pregnancy.

And since so much preparation goes into welcoming a new life, most moms and dads want to get it just right the first time, which means knowing exactly when to expect their newborn.

A baby’s approximate due date can be determined a couple of different ways, the most common of them being based on a woman’s last menstrual cycle. Many calculators can be found online to help you determine this but the formulas is pretty straightforward. Simply take the first day of your last menstrual period, minus 3 months and then add 7 days. So for instance, if the first date of your last period was June 1st then you would minus 3 months, which would be March 1st and add 7 days which would be March 8th. So therefore your approximate due date would be March 8th of the following calendar year. This estimate will easily equal out to the estimated 38-40 weeks of gestation or 9 months of pregnancy that we are all well aware of.

But bare in mind that this method does present some limitations. It is more accurate for women who have a regular, consistent menstrual cycle, or one that “works like clockwork” so to speak. This is because the length of your period as well as its frequency must be taken into consideration when calculating. If you’re not too sure about this part, you can try some keyword tools to further understand how the menstrual cycle is supposed to work. Women that have irregular periods with different starting dates or lengths that are uncertain may not be able to calculate their due date accurately using this method.

Another, more accurate and preferred method of due date calculation, is to utilize the results of an 8-10 week ultrasound. Your practitioner will likely request that you take an ultrasound during your first trimester. This first ultrasound will often provide you with a more accurate prediction than the previously mentioned calculation. During this examination the technician will exam different parts of your baby such as the head, thigh, and stomach, to determine their appropriate age. If the size is off by even a few weeks it is usually detected and your due date will be changed to reflect the ultrasound reading.

Though in any event, all calculations whether electronic or using the menstrual cycle method, should be understood as only estimations. There is no sure way to tell exactly when your baby will be born as even ultrasounds can be inaccurate. There is actually a margin of error of about 1.2 weeks for ultrasounds that should be noted. And likewise, later ultrasounds are much less accurate in predicting due dates than the first ultrasound. So for instance, it’s not uncommon for a baby to be born two weeks before or after the estimated due date. So it can be understood from this that there is always that small window of uncertainty.