Updated: Feb 9, 2022
What's your due month?
I don't think women realize that two weeks are automatically added on to your ESTIMATED due date.
"Your due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual cycle). Note, that your menstrual period and ovulation are counted as the first two weeks of pregnancy. If you deliver on your due date, your baby is actually on 38 weeks old, not 40."
This is something that I explained in one of my blog posts called "The Truth About Inducing." I'm not sure why women (who should know how ovulation works), don't realize that YOU DID NOT GET PREGNANT DURING YOUR PERIOD. So how can your due date be calculated based on the the first day of your last cycle? There is no such thing as a due date! You can only get pregnant when you are ovulating. And the majority of women who have a regular cycle, ovulate TWO WEEKS after the first day of their cycle. See what happened there? See where that extra two weeks came from? Makes sense now doesn't it? This is why they say women can give birth two weeks before, or two weeks after their estimated due date. Because a due date is JUST A GUESS. That's why it's called an EDD, Estimated Due Date!
So when you try to induce at 37 weeks, umm...you're really only 35 weeks. This is why for the past 7-8 years, full term is now considered 39 weeks and not 37 weeks. They gave you those two weeks back to ensure that your baby is fully developed. At 38 weeks, baby's lungs and brain are still growing!!
"But what if my doctor says my baby is measuring ahead? That means my baby is fully developed and I can induce myself" Umm, no! My daughter is 11 years old, if she looked 15, does that make her 15 years old? Nope! She's still 11 years old...just big for her age. Just because your baby is measuring ahead, doesn't mean the gestational age has changed.
From Fear Free Child Birth
"Your period length was not taken into account. As with your ovulation cycle, it’s unlikely that you were asked this information. And even if you were, is this something that you know?“ But I gave the date of my last period!” You were probably asked the first date of your last period (LMP), but to take this information in isolation without your ovulation cycle and length of your typical menstrual cycle, just adds to the inaccuracy. In absence of accurate menstrual information care givers will likely assume that your menstrual cycle is 28 days and that you ovulate half way through your cycle (on day 14). But menstrual cycles can vary in length from 25 to 37 days. And, ovulation doesn’t always happen half way through a cycle; if you’re stressed or recently off the pill then you won’t. So depending on the finer details of your menstrual cycle, your due date could be up to a week or more out… and that’s before we look at the fact that the method used to calculate your EDD is not even a sensible one!What can I do? Speak to your midwife or birthing care provider to understand what they based your due date on. Ask them if they took into account the length of your menstrual cycle and your ovulation cycle. Ask them which due date calculation method they used. So, what IS my due date? Of course, when the time comes, it’s all down to baby and when baby is ready. But, if you find yourself going past your due date and facing the pressure to be induced, wouldn’t be helpful to have more confidence in the date that your baby is likely to make an appearance by?"
Take it all in ladies...take it all in. Because your due date is a guess, STOP STRESSING when your baby hasn't arrived by your estimated due date. Your baby just isn't ready yet!