For those of us who have had babies past our EDD, the struggle of waiting for our baby was REAL. I know all too well what it’s like to have a baby past the estimated due date, both of mine were over by a week or more and boy it was hard! People make comments like “you STILL haven’t had your baby yet?” and the days seem to drag on and on after that much-anticipated date. I’m with ya ladies, but today I want to talk about why going past your “guess date” (as us doulas in Edmonton like to call it), though annoying, does have it’s benefits.
Where does your estimated due date come from?
Our estimated due date, or EDD as it is referred to by many Edmonton doulas, is measured a couple of different ways. The most common way is by determining the date of your last menstrual period (LMP in cyber lingo) and counting exactly 40 weeks from this date. Technically that makes you two weeks pregnant even before you conceive… weird hey? Well because it’s virtually impossible to know exactly when a female ovulates without being closely monitored by a health professional, it’s easier to just measure the length of a pregnancy by their first day of their last period. However, there is tons of room for error in this method as women are all unique when it comes to cycle length and time of ovulation. This basically assumes that all women have identical cycles every month!
The other method of measuring your EDD, which has a bit more accuracy, is an early ultrasound in your first trimester. The ultrasound tech will measure the baby in a variety of different areas and base their age on an average of other babies at this stage. The problem with this? Humans are all different, especially in their rate of growth. A baby may be the size of an 8 week old fetus, but is actually 10 weeks old and just hasn’t hit a common growth spurt yet. Once again, not a very accurate measure of the age of a baby.
So you now can see why us doulas in Edmonton call your EDD a “guess date”. Aside from the level of accuracy of these tests, how do we know that humans gestate for exactly 40 weeks? There have actually been studies that show that 40 weeks and 5 days is a more accurate measure of gestation, but all women and babies are different.
What does your estimated due date actually do?
So if this date is such a crap shoot, why even bother with one?
Well, it is important to know approximately how old your baby is for various reasons. The first is to ensure that baby is growing and developing at a normal or average rate. Knowing how old a fetus is at the 20 week anatomy ultrasound will determine if the baby’s various parts are in a normal size range for their age.
While not all babies grow at the same rate, there shouldn't be too much difference between what one 20-week baby looks like to the other. Another reason to know the EDD is for viability purposes. If you were to come down with an illness in which it would compromise you or the baby’s health to stay pregnant, such as preeclampsia, your health care provider will want to weigh the risks of inducing or performing a cesarean at the age they are at vs. letting the baby gestate a bit longer. Generally speaking there is an age where a baby is more likely to survive outside the womb, but the longer baby an stay in utero the better (for the most part).
What happens if you go over… like, way over?
A common misconception that is out there and one that I’ve fallen for is that in a normal, low-risk pregnancy, a baby cannot stay in utero past 41 weeks. Or even worse, people really do believe that their baby does not know when they are to be born safely. If you look at the evidence-based research and information out there, this is just not true! First of all, since we haven’t determined exactly how old your baby is or how long he/she needs to gestate for, what sense would it make to cut baby off at what we think is 41 weeks? When I ask people this question, many reply with “but I can just get induced and it will be fine”. Yes this may be true for many, but inductions do carry many risks to both mom and baby. It has also been suggested with many studies that your baby is the person who decides when you will go into labour. Your baby is the one that triggers the specific hormone releases days, hours and even minutes before they are born.
Disrupting this physiological process has consequences and has been shown to increase a woman’s chance of postpartum haemorrhage, breastfeeding issues and postpartum mood disorders. It’s important to not panic when baby has not come on their guess date, as your baby knows when they are ready for life outside the womb. There are obviously cases where baby coming out before this date is best for the health and safety of you both, but for the most part it’s an instinctive response that baby should make on their own.
Click on the links to learn more about the current evidence on due dates and Induction.
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