Beyond Due Dates: How Late is Too Late?

Once our children are born, it seems we have infinite patience for the great diversity and variety of growth and development among them.  One gets teeth at this age, another a month later.  My first walked at 9 months, my 2nd at a year and so on.  We even seem to take it all in stride that one baby weighs in at 6 lbs. 7 ounces while another at 9 lbs. 2 ounces.  Why then are we so quick to believe that millions of babies will somehow, magically be ready to be born at precisely the same time in their gestation?

Try though we might, none of us can quite believe that we don’t have a due date.  EDD actually stands for estimated date of delivery, not due date. Personally I much prefer EDB (estimated date of birth) and certainly not the original term EDC (estimated date of confinement). No matter what you call that date on the calendar, it is nothing more than a formula derived from statistical averages which says that sometime within a range of 4-5 weeks your baby will probably be be born. Smack dab in the middle of that range is one of days on which the labor may start.  Yet when it comes to dates in our life, few take on more significance than this one.

As absurd as this sounds, we live in a culture where giving birth beyond the ‘due date’ has become pathological. Normal physiological gestation in a human is 37 to 42 weeks.  The World Health Organization, the American College of Obstetricians & Gynecologists, the International Federation of Gynecology & Obstetrics, and the Society of Obstetricians and Gynaecologists of Canada all define ‘post term’ pregnancy as continuing beyond 42 weeks.  Translated, this means that before 42 weeks is not post term.  (Past due, post dates and post term are phrases used to discuss this issue, but the current preferred terminology is ‘post term’.)

In 1998 approximately 18% of US pregnancies lasted beyond 41 weeks and of those 10% went past 42 weeks. By 2005 these figures were down to 14% and 6% respectively.  Multiple factors are contributing to what is called this “shift to the left”. One positive change probably derives from increased accuracy in the dating of pregnancies through earlier ultrasounds, thus eliminating ‘pseudo’ post term pregnancies.  But it is likely the main reason for the decrease in births beyond the EDB is the increase in technological deliveries (inductions and cesareans), many driven by concerns for the increased risks of pregnancy in the post term period. Indeed, in Listening to Mothers II, “caregiver concern that mother was overdue” was reported by mothers as the number one reason for inductions of labor. In addition, the overall increase in elective and interventive births for all reasons has precluded more and more pregnancies from reaching their 40th, 41st and 42nd weeks.

For the woman whose pregnancy continues well beyond her EDB, the issues surrounding post term pregnancy are important. This can be a scary time. We are told that the risks of fetal deaths increase the farther past our due dates we go and therefore (at some point) it becomes safer to induce labor than to wait. But what is that risk? For which mothers and babies? When?  What is the evidence? And… does it apply to me?

On the one hand, who really wants to think about or discuss the issue of babies potentially dying when you’re a healthy mom with a normal pregnancy?  But let’s talk about it. Let’s talk about it because not knowing and understanding this issue makes it much harder to make informed choices when and if the time comes to choose what to do once someone’s pregnancy moves past “half-time” (your EDB).

To this end, over the next few weeks, Science and Sensibility will publish a series of posts on Post-Term Pregnancy to explore and discuss the following:

  • ‘Am I a Ticking Time Bomb or What?’ – Unraveling the Evidence Behind Post Term Pregnancy as a Time of Danger
  • ‘Watchful Waiting or Induce?’ – The Complex Issues of What to Do When Baby Hasn’t Come
22 Comments

Beyond Due Dates: How Late is Too Late?

October 15, 2009 07:00 AM by Stuart Fischbein
Thanks for sharing your thoughts. You are right to ask the question. Reminds me of one of my favorite quotes: "A long habit of not thinking a thing wrong gives it a superficial appearance of it being right." Thomas Paine Looking forward to reading the author's subsequent posts.

Beyond Due Dates: How Late is Too Late?

October 15, 2009 07:00 AM by Nicole
This is so wonderful & I can't wait to read the coming articles. It drives me crazy when I am getting report at work & I am told the patient I will be taking care of is being induced because she is "post dates" & I look at her records & find she is ONE day past her due date. I could SCREAM!!! I will usually say "oh so this is really a social induction" & smile. the other nurse is always like "well yea but..." When I first started this journey in women's health it was nothing for women at my hospital to stay pregnant until 42 weeks. Now its like ther must be something wrong. Its an interesting situation & so many things @ play. Okay... enough of my ranting. :-D I look forward to the articles!

Beyond Due Dates: How Late is Too Late?

October 15, 2009 07:00 AM by Rosie
Mary Sadagy Leslie! so great to read you here! San Diego misses you. Isn't it true that EDD originated by Harmanni Boerhaave, a botanist who in 1744 came up with a method of calculating the EDD based upon evidence in the Bible that human gestation lasts approximately 10 lunar months. The formula was publicized around 1812 by German obstetrician Franz Naegele. There is one glaring flaw in Naegele's rule. Strictly speaking, a lunar (or synodic - from new moon to new moon) month is actually 29.53 days, which makes 10 lunar months roughly 295 days, a full 15 days longer than the 280 days gestation we've been lead to believe is average. We're long OVERDUE to right this wrong.

Beyond Due Dates: How Late is Too Late?

October 15, 2009 07:00 AM by Angela Gunther, LCCE
A few months (maybe a year) ago, there was an article in Parenting magazine about a mom who's baby "didn't come on his own" so the mom had to be induced. This mom was 10 days past her due date. Who knows if this baby would have come on his own a day or two later?? At least she was allowed to go 10 days past. But this article was a reflection of our culture and another message to moms that induction is normal. Also, moms are so worried about baby getting "too big"! I always tell couples in my classes that up until 42 weeks is normal and most moms will go 7-10 past but some even longer. I tell them to forget the due date and focus on the range of time. Not all babies gestate the same amount of time and conception dates and ultrasound measurements can be off. Even so, I still have couples in my class who are induced just days after their due date. I really want to give moms facts about the risks of inducing a baby at 39-41 weeks. What if the u/s is off by a week? How does that affect baby's development? - that's what mom's need to know! My babies were all "past due" by at least 9 days. I did not have an u/s with my second pregnancy but was "positive" of the day we conceived. My son was born 13 days past his due date covered in vernix!

Beyond Due Dates: How Late is Too Late?

October 15, 2009 07:00 AM by Ami Burns, LCCE, FACCE
Great post -- one of my favorites so far. This is the #1 topic that comes up in my classes -- that and the "doc is afraid my baby is too big" Can't wait for the next post!

Beyond Due Dates: How Late is Too Late?

October 16, 2009 07:00 AM by Maia
A fellow mother in my hynobirthing class was pregnant with her third baby. She had pretty traumatic birth experiences with her first two pregancies because she had gone "past her due date" so she was induced. The third baby she went with a home birth and gave birth to a healthy baby 19 days past her "due date". She just has a longer gestational period than others and she finally found a provider that respected and embraced that!

Beyond Due Dates: How Late is Too Late?

October 16, 2009 07:00 AM by NursingBirth
Thank you so much for posting about this. We often, and I mean OFTEN, get obsetricians and midwives regularly inducing their patients for "post dates" at 40.1, 40.2, or 40.3. The more "liberal" (and I mean that lightly) docs and midwives will wait until 41.1, 41.2, or 41.3. There are only 2 docs and 1 midwife out of the 21 OBs and 7 midwives that attend births at my hospital that will only set up an induction for "post dates" at 41.5 days (assuming that many inductions take 2 days, they figure, at 41.5 the baby would be born no later than 42.0). I mean I can look at the induction book on any given day and 4 out of the 6 inductions for the day are BOGUS. And ALL the attendings I have talked to about this pull the "dead baby card" as their reason for inducing for "post dates" when a mother is only days past her "due" date. It is extrememly frustrating. ~Melissa aka "NursingBirth" www.nursingbirth.com

Beyond Due Dates: How Late is Too Late?

October 16, 2009 07:00 AM by Carolyn Hastie
Dear all, This is a great conversation. I particularly like the comment by Rosie: "Harmanni Boerhaave, a botanist who in 1744 came up with a method of calculating the EDD based upon evidence in the Bible that human gestation lasts approximately 10 lunar months. The formula was publicized around 1812 by German obstetrician Franz Naegele. There is one glaring flaw in Naegele’s rule. Strictly speaking, a lunar (or synodic – from new moon to new moon) month is actually 29.53 days, which makes 10 lunar months roughly 295 days, a full 15 days longer than the 280 days gestation we’ve been lead to believe is average". Now this requires publishing more widely. I'm amazed myself at how the 'acceptable' timeframe for so called 'post dates' has been so contracted in the last twenty years. It is totally insane the way as Nursing Birth has said that 'they' pull out the 'dead baby card' as a means of manipulating compliance to 'their' agenda. I'm darned if I know what triggers this urge to control women with babies in their bellies. As soon as those babies are out, people can do what they want (pretty well). We had five people die on our local beaches last summer, but there isn't this hysteria (like there is about induction for 'post dates' because babies might die etc etc) about keeping people out of the water!

Beyond Due Dates: How Late is Too Late?

October 18, 2009 07:00 AM by jane
as a slow cooker of babies thankyou for this thoughtful article... it should be compulsory reading for obstetricians here who make rules that are so draconian about this kind of thing

Beyond Due Dates: How Late is Too Late?

October 19, 2009 07:00 AM by Claire Winstone
An induction that takes 2 days (or longer) is by definition trying to start a labor for a baby who isn't ready to be born. The number of oxytocin receptors in the uterus increase exponentially the closer you get to the day labor would start spontaneously so if you're flooding too few receptors with too much oxytocin labor just isn't going to start easily. Not to mention that no-one asks the question "what does it mean for mother and baby if their systems (i.e., oxytocin receptors) are flooded with artificial stuff (Pitocin) that doesn't facilitate bonding or lactation?"!!! Simply having the same chemical structure as oxytocin doesn't mean Pitocin operates the same way--we know it doesn't! One more comment--“doc is afraid my baby is too big” sounds like incompetent OB. How come midwives don't freak out about big babies and actually know that any size baby might have a dystocia--and how to resolve it?

Beyond Due Dates: How Late is Too Late?

October 19, 2009 07:00 AM by MLS
As a mother who went to 41 wks with baby #1 (so technically, quite average for a 1st timer, not "late"), and then to 43 wks + 3 days with baby #2, I just want to bang my head against the wall when I hear anyone (be it OB, CNM, or mother) talk about "had to be induced." Of course, with each of my babies, the OBs got antsy right around 39 weeks, starting to mention induction despite my being very clear and calm and consistent about having NO INDUCTION unless something was truly medically + urgently wrong with me and/or the baby. With baby #2, we planned a homebirth and also sought parallel care with an OB in the small event that we'd need to transfer (unfortunately not telling the OB about this because that's the climate in our city - OB won't touch you if planning a homebirth). Thank goodness we had our homebirth midwife this whole time! Through our OB office, I was consenting to NSTs and BPPs as week 41 turned into week 42 (it made them slightly back off the "induction chant"), with ever increasing pressure and scare tactics. Even the ultrasound tech was rude to me, trying to tell me how "old and calcified" my placenta was (that was a new one!), asking me if I was a heavy smoker (um, hello?!?! not a smoker at all, ever!), basically trying to scare us about everything under the sun DESPITE baby's numbers and activity looking great, my fluid levels being just fine, etc., etc. On the day of my 42nd week of pregnancy, I left my OB practice officially and politely, kindly thanking them for their care up to this point, and preemptively providing an AMA letter that both my husband and I signed. We simply stated that we understood their discomfort with my being 42 weeks pregnant, but no medical problems had been detected with mom or baby so we were looking for expectant management and not medical intervention, and that we wanted to release them of any liability since we had another care provider to attend our birth. That very night, the OB called us at 8pm and literally YELLED at me over the phone for 20 minutes, totally playing the dead baby card over and over. I remained calm only because she was so rude and absurd and obviously manipulative that I couldn't believe it was possible to treat a patient like this (any other person would be fired at this point in their job for such horrid "customer service"!). So the OB demanded to talk to my husband (I humored her) whom she tried to brow-beat with some made-up idea that we had *contractually* agreed to an induction and *must* show up that very night at the hospital for immediate induction (huh? what? and with what imaginary contract?!). She even went so far as to say to us incredulously, "So, what then, will you have your baby by yourself in the kitchen sink?!?!?!" It was UNREAL. I am extremely excited to read your upcoming posts on what the current US maternity system calls -- erroneously, IMO -- "post term." THANK YOU for addressing this issue, and it would have been lovely to have these posts as a reference 4 yrs ago when I was dealing with my "post term" pregnancy. By the way, my post term baby was born FULL of vernix and wasn't in the least bit "overdue" though if I'd allowed the OB dictate it all, I would have had a baby who was EARLY by almost 4 weeks (remember, they start offering at week 39). Currently expecting baby #3 and very curious to see what this one's gestational period turns out to be!

Beyond Due Dates: How Late is Too Late?

October 20, 2009 07:00 AM by Christy
I'm looking forward to learning more about this. Thanks.

Beyond Due Dates: How Late is Too Late?

October 20, 2009 07:00 AM by MomTFH
At the birth center where I trained as a midwife, we did biophysical profiles on anyone who went post date. Unfortunately, we were legally required to transfer care at 42.0 days. I was a doula for a grand multip who went 10 days over with every pregnancy, just like her mother. She started post dating her FDLMP when she presented at each initial prenatal visit, so they ob/gyn would not start pressuring her to induce when she invariably went post date.

Beyond Due Dates: How Late is Too Late?

October 21, 2009 07:00 AM by Amy V. Haas, BCCE
You are correct Rosie! The length of normal human gestion has been estimated to be longer than nagel's rule --- there was a study done, but no one seems to know about it. they estimated that the average for a 1st time mom is actually 41 weeks and one day. This takes the "over due" date out to 43 weeks and 1 day. apparently 99% of women will birth by then. I am also floored by the alternating arguments care providers use - " your baby will grow too big--" (fear of shoulder dystocia) " your system will stop working--" (fear of postmaturity syndrome) so wait a min. --- which is it? The system shuts down, or the baby keeps growing? Make up your minds!!!

Beyond Due Dates: How Late is Too Late?

October 21, 2009 07:00 AM by Amy V. Haas, BCCE
@Claire Winstone actually, sometimes midwives do freak out about size. I am thinking they may be ones who fear shoulder dystocia. Are they not taught the Gaskin Maneuver?

Beyond Due Dates: How Late is Too Late?

October 27, 2009 07:00 AM by Sally Westbury
personally i am frustrated by the question. so.. how long will they let you go over?? i tell women... who are they??? when did they take possession of my mind and body. Each woman is capable and competent to assess risks and benefits and decide what will happen to her body and her baby. Having waited recently for spontaneous labour until 46+1 day past her EDB. I trust women.

Beyond Due Dates: How Late is Too Late?

November 20, 2009 07:00 AM by Twitted by 4manspeak
[...] This post was Twitted by 4manspeak [...]

Beyond Due Dates: How Late is Too Late?

December 23, 2009 07:00 AM by Helen A. Loucado, RN LMT CLA CIIM CLC
Mayri, so glad to see you here! I really appreciate your approach to this topic and will share it with clients. I attended a labor support workshop you taught in 1999 through ALACE. Loved it, so inspiring. This whole issue of being considered post dates is very stressful for moms. Last month a woman who took my birth class asked for natural things to get labor going because she didn't want the pressure and stress from her OB about going 41 weeks. This is just insane. Even women who have midwifery care are affected. So pleased to have your logical,intelligent voice to this discussion.

Beyond Due Dates: How Late is Too Late?

February 1, 2010 07:00 AM by Laura Setiu
Thanks for bringing up this topic. I have had 3 boys who have all been 41- 42.5 weeks 'overdue'. There is so much social pressure when you go past your due date as people start asking on a very regular basis "have you had your baby yet" and "when are you going to be induced" and "oh i would get an induction...it's been long enough already". As a society we have squeezed childbirth into our 'control' box and that to we want to have on schedule. I have been blessed to be supported by 2 midwives who were more than happy to watch and wait.

Beyond Due Dates: How Late is Too Late?

February 1, 2010 07:00 AM by Sherwood
Very good topic. I have known people whose babies with a month early and nearly a month late- all were healthy. As one mom said "I think everyone's oven cooks at a little different temperature" :) The pure absurdity of forcing a healthy baby out early is wrong from so many different angles. AND more importantly, Dr.momma blog recently did a closer look at induction, and upon reviewing the pitocin package insert found out that pitocin is contraindicated by the manufacturer for inducing labor, rather it's a "augmentation" for failure to progress- another beauty :( It is appalling to hear these stories of psychopathic OBs on insane power rants over pregnant women, and know that this happens everyday all over this county and the world- thank you increasing awareness and for sensibility!

Beyond Due Dates: How Late is Too Late?

May 12, 2010 07:00 AM by ElElRi
I'm at the age where tons of people I know are having babies (24, so my friends are all 22 - 32) and I see this over and over again. And when it rarely ends without a c-section or horribly traumatic delivery I'm happy, but it sadly usually has not for people I know. I went to almost 42 weeks and was told repeatedly by the midwives that I really "need to get this labor going" after 40 weeks 3 days, and was told to speak to the OB about it, and the OB kept saying my decision not to induce, based on my own research, was "interesting".. I'm guessing he did not see women refuse induction much. And even without an induction after my hospital experience with those midwives and that OB, I've decided being in a hospital for my future births - barring emergency - is not a good option for me, so home birth it is for my future kids with or without a midwife (if she stops seeing people at 42 weeks, oh well, I'm not doing what I did last time. No way.)! I try to spread the word about what is evidenced based.. I shared this with some pregnant friends because the comments in here are exactly the sort of thing I think about this. I look forward to the rest of this!

Beyond Due Dates: How Late is Too Late?

May 12, 2010 07:00 AM by ElElRi
Oh you should've posted the rest of these articles I'll have to look for them.

To leave a comment, click on the Comment icon on the left side of the screen.  You must login to submit a comment.  

Recent Stories
Preventing Maternal Deaths Act Bill Passes US House of Representatives!

What's to LOVE about LamazeLIVE 2019 - Start Planning Now!

Research Review: Evidence of Racial Disparities in Access to Human Milk in the NICU