Tag Archives: EDD

Monday Musing… Don’t Change That Date!

Over the years I have heard a lot of pretty ridiculous things OB providers have told women. I have heard women verbally bullied and virtually forced into hospitalizations, procedures, inductions, tests, etc in the name of “safe obstetrics.”  The other day I was completely enraged because I was reminded, some doctors are taking the bull shit to a whole new level.  I’m convinced many of them REALLY believe women are stupid and incapable of making good decisions. 

I have a friend whose sister is pregnant.  During a recent conversation I asked about her sister.  I was especially concerned since the last time we spoke her sister was being referred to the MFM (Maternal Fetal Medicine high risk folks) because something on her early ultrasound was suspicious for downs syndrome. 

My Friend:  “Well… that  issue (The Downs Syndrome) has been resolved apparently because they have discharged her from the MFM BUT…. Now, the new thing is… her doctor is telling her he thinks she is going to have the baby early…. “

ME:  “HUH?? WHY??? What do you mean??? Shit… he is already setting her up mentally for an induction…  What’s her due date?” 

My Friend:  “Well it was March 8th but at her last appointment he felt like she might go in early. Told her she might be ready around February 28th”

ME:   *gasp* “Are you F-Bomb kidding me??!! That’s bull-shit. She had multiple ultrasounds with the MFM. If her due date needed to be changed they would have said something.  You don’t just all of a sudden change somebody’s due date at this stage. He is setting your sister up so he can schedule an induction. She will be 39 weeks then. That’s some straight bullshit. Tell your sister to call me.”

My Friend:  “Wow…. She has said she definitely doesn’t want to be induced”

Me:  Well he is playing games and setting her up for an induction. Putting bull shit in her head now makes it easier for him later. Tell your sister to call me…

I was pissed!!!  The bottom line is this:  The earlier the ultrasound, the more accurate the estimated “due date” (EDD) Each time you get another ultrasound it is possible that they will give you a new “due date.”   Regardless of the so-called new due date your original due date DOES.   NOT.   CHANGE. 

Ultrasounds and their ability to predict due dates are affected by a number of things including but not limited to:  the skill of the person doing the ultrasound, what they measure to obtain the date, the approximate gestational age of your growing baby, and the percentile growth or size of your infant.

Most women these days get at least two ultrasounds.  The first ultrasound, usually called your “dating ultrasound” is done as early as possible.  If it’s done during the first 12 weeks of pregnancy, it is the best predictor, after the date of your last menstrual period (LMP), of your EDD.  It is pretty accurate to a few days.  If the difference between your LMP due date and your first trimester ultrasound due date is more than a week, your provider will assign the ultrasound due date. If the difference is less than a week, they should go with your LMP date but many don’t. IMO its because they are more comfortable with technology than they are believing a woman knows her cycle but that’s a post for another day.

Some where between 18-22 weeks most women receive their second ultrasound, often called an anatomy scan.  As your baby grows and is somewhere on either side of “average” this anatomy scan may produce a different EDD, but it does NOT  really CHANGE your due date.  An ultrasound at this gestational age is not as accurate as the earlier ultrasound.   If you have a good ultrasound during the first twelve weeks of pregnancy, there should be no reason to change your due date.

After the first trimester, ultrasounds have a margin of error of up to 10 days.  After 26 weeks of pregnancy that margin of error increases to THREE  WEEKS!!! That’s up to 3 weeks wrong in either direction.  This means if you did not have an early ultrasound, and you don’t know your LMP, and you get an ultrasound that says you are 32 weeks… you could be anywhere between 29 and 35 weeks. That is the nature of the ultrasounds.

If you had your initial ultrasound during the first 12 weeks of pregnancy, or shortly thereafter, be VERY leery if your provider wants to change your date, especially to an earlier date.  Just because your baby may “measure big” does not mean that your baby is gestationally older. It just means you have a baby on the high side of average.  (Not that “measuring big” is all that accurate anyway but that’s also a post for another day)  If you are like my friend’s sister, and you had multiple ultrasounds, and all of a sudden your provider tells you they need to make your due date earlier… all I can say is RUN!!!  Or at a minimum get to asking some SERIOUS questions. Your birth experience and may depend on it.

Were you constantly confused because your due date kept changing? Were you induced because of a new due date that made you  “post dates?”  I would love to hear about it.