Due dates, "postdates", etc

Because Rixa received some "interesting" comments on her due date entry....

I hear the term "postdates" being used all the time for women a day past 40 weeks gestation. What is frustrating is the true definition of being "postdates" is when a woman's pregnancy goes beyond the 42nd completed week.

Then again, when we live in a world where women rarely reach 42 weeks (and even some of those women need to cook longer, or are using ultrasounds to rely on their "due date" thereby increasing the error of "dating")...in fact, it's much more common to induce PRIOR to the magic "due date".

Women are not a carton of milk. We do not have an 'expiration date'. Did you also know that our bodies are not going to hold that wee little babe in until that mother damages it? Did you know that our bodies and babies often work together as far as determining when labor truly does start? Amazing, isn't it?? /sarcasm

Here is my informed choice agreement on Postdates (in pdf). Now, I usually give it to women at the end of 41 weeks because that is when they are conditioned to start worrying. "How long will they let you go??", nosy relatives ask. (One client had this great response: "Well, see, I fired THEY. I'm in charge now!") When you live in a culture that induces BEFORE the "due date" surely there must be something DANGEROUS about going past that date, right?

I won't even get into prenatal vaginal exams and how everyone on earth wants to know the ins and outs of that uterine opening inside your vagina. It's amazing to me how we get so personal so fast...and if you don't have those exams (*gasp!*) then it makes people get all crazy. No information? How will you know if you're close to labor?? (Again, how does this information help women? Really, how does it? It's all about judgment and "progress", resulting in more judgment and anxiety)

Oh and then there's postmaturity syndrome. Which has little to do with dating - and more to do with uteroplacental insufficiency. It can happen at 37 weeks, it can happen at 40 weeks, it can happen at 44 weeks. It's not about dates, but about a baby that has gone beyond what the placenta can adequately sustain..but the amazing thing is that the placenta keeps going! With postmaturity syndrome, the placenta is trying. True postmaturity syndrome can ONLY be diagnosed with a newborn exam (i.e., after the birth). Our placentas do not "die"...they do not rot off our uterine wall. In fact, when the placenta is aging (as it does), it branches out looking for new areas of uterine freshness - and also increases the blood pressure to maximize the volume of blood coming to it and subsequently the baby.

That's why so many women are diagnosed with "pre-eclampsia" in the last few weeks of pregnancy based on blood pressure readings (and a dipstick usually showing dehydration, resulting in proteinuria). Instead of looking at what is physiologically normal, an assumption is made that the woman's body is getting toxic from this baby and baby must get out!

To be sure, pre-eclampsia does happen. I'm not saying that it doesn't. However, it is extremely rare to just occur in the last few weeks of pregnancy. It's a disease that starts at the beginning of the third trimester and the six weeks that follows. The correlation with having a contracted blood volume is too remarkable to go unnoticed...and we know that the blood volume of a pregnant woman should peak around 28-30 weeks gestation.

Oh, the tangents I get off on. It's just all so silly, applying linear rules and guidelines to a woman's body...women are NOT linear, our babies gestation times are NOT linear. However we are subjected to the linear conveyor belt of this thinking repeatedly. This isn't about the medical model - it's about a huge percentage of providers, midwives, too!

I agree with Laborpayne and my apprentice: there should be a "due month" given. We live in a society that would NOT accept that. Even mothers wouldn't accept it. The date - the precise date - has to be circled on the calendar. Heaven forbid if you go past that...then there must be something wrong with YOU.

Oh and don't even get me started with biophysical profiles, low amniotic fluid levels and placental grading at term. Again, it all has to do with evidence-based practice vs litigation-based practice.