After enduring back pain, sleepless nights and a host of other discomforts related to pregnancy, many women are all too eager to welcome the last weeks of pregnancy, thinking that when their due date is near, labor can begin anytime. But how accurate are due dates really? And what happens when you go beyond your expected date of confinement or EDC?

Your due date or expected date of confinement is calculated in several ways. A conventional way of calculating a woman’s due date is by using Naegele’s Rule or simply by subtracting three months, and adding seven days from the first day of the woman’s LMP or last menstrual cycle. You may also need to add 1 to the year when necessary.

Here’s an example:  LMP – September 12, 2010:

1.       Add 7 days: 12 + 7 = 19

2.       Subtract 3 months: For September, moving back three months would be June

3. Adjust the year when needed: For this case, 2010 + 1 year =  2011

By utilizing the Naegele’s Rule with the above LMP, the due date would then be June 19, 2011.

Another method widely used by health care providers is estimating the due date by using a pregnancy wheel. Your doctor can easily determine a date by lining up the date of your LMP with the indicator. While these may sound so easy, doctors have to consider whether you have regular cycles because many of these methods are based on a woman’s average cycle length which is 28 days.

There is also a need to compare your due date based on your LMP with an ultrasound test during the first trimester of pregnancy. Ultrasound tests during the first trimester are more reliable in determining gestational age because early fetal growth tends to occur on a regular schedule. During the latter part of pregnancy, fetal growth rates can greatly vary thereby making ultrasound results inaccurate parameters in predicting gestational age.

However, it’s important to keep in mind that doctors can only go as far as making an educated guess by calculating using your LMP and through ultrasounds, but not any of these methods can accurately tell as to when labor will begin. In fact, studies even show that only a small percentage of women actually go into labor during their due dates.

So as you approach the last trimester of your pregnancy, don’t expect labor to begin on your due date. Enjoy the remaining weeks of being pregnant, and adapt a wait and see approach. Labor that begins a week before or after a woman’s due date is still considered normal so stay in touch with your doctor, relax and wait some more. Pregnancy is only considered post-term or overdue if it goes beyond two weeks, so hang in there.

If you still find yourself without any labor signs a week past your due date, your doctor may already monitor your baby’s heartbeat twice a week. He may also order an ultrasound to determine the level of your amniotic fluid. Further, your doctor will also check whether your cervix is dilated and thinned in preparation for labor. At this point, it’s important to keep track of your baby’s movements. If you notice that your baby doesn’t move as much anymore, call your doctor immediately.

The last few weeks prior to delivery can seem so long especially when you want nothing else but to be free from the menacing symptoms related to the last trimester of pregnancy. But before you try any activities or tricks that are believed to initiate labor, talk to your doctor first. It’s the last stretch of your pregnancy, and all the more you need to work hand in hand with him in ensuring that everything is going well for you and your baby.