The Truth About Due Dates

September 27, 2019

Scrolling through all my mommy groups this week, I came across almost this same exact post (or some variation of it) too many times to count! 


"HELP! I'm 40 weeks pregnant today and seeing NO SIGNS of labour! How can I induce labour!? I don't wan't to go overdue or be induced!" *Insert all the crying, sad and panicked emojis* 


Now. As a Doula, I try my very best not to comment on these posts other than to encourage mama to rest, eat, stay hydrated and maybe try some sex/nipple stimulation if shes up for it. Followed by "Don't worry, babies come when they're ready". That said, having birthed 3 babies of my own, I know my "sage advice" isn't likely to break through to the mom who's feeling tired, sore, anxious, disappointed and SO DONE with pregnancy. 


In all honesty, I'm not surprised this is such a common post! In fact, given how we as a culture think about due dates and all the "why are you still pregnant" questions a mom gets as soon as she reaches her estimated baby day, it's no wonder she too might begin to worry or become impatient should baby choose to extend their stay inside her womb! This is completely normal and those feelings are 100% valid! 



Here's the thing. Sometimes induction really is the best course of action for SO many reasons. However, in the absence of any clear medical reason for induction (and no, big baby, maternal age, or "past your due date" are NOT on that list), its good to know the REAL FACTS about due dates in order to avoid all kinds of anxiety, disappointment and even unnecessary induction and interventions when your body would have otherwise done exactly what it was designed to in its own time. 


So here is the real deal about estimated due dates (estimated being the key word there). Hopefully, having this information is enough to ease the anxiety and disappointment of any expecting (and "past due") mother. 


More of a Guess Than a Science


Believe it or not, due dates didn't come from a calculated, peer reviewed study. It might surprise you to find out that the "science" behind the "40 weeks" gestational period was more of an educated guess based on the average growth rate of a human fetus and the average 28 day menstrual cycle (ovulation occurring smack on the 14th day), give or take 7 days. I know. NASA level stuff. This is what that "pregnancy wheel" your healthcare provider uses to determine your "due date" is based on!


First of all, we know that a normal menstrual cycle (in the absence of contraceptives like an IUD or the Pill) can be anywhere from 24 - 38 days and if you've ever tracked your cycle for either birth control or to try and conceive, you know the MONSTROUS task it can be to pin point the exact day you ovulate. In fact, I would argue that without the help of an ultrasound or other medical tests, its darn near impossible. Even in women with the most regular cycles, ovulation can occur a few days before or even after that "mid cycle" point due to normal hormonal changes caused by stress, fatigue, diet, physical activity and SO many other factors. 


All that considered, it stands to reason that a blanket "40 weeks from day one of your cycle" may not be accurate in every pregnancy.  


What We Know Now


Thanks to many more years of research and statistic records, we now know that the average gestational period for first time birthers is actually closer to 40 weeks and 5 days rather than the estimated 40 weeks. Not only that, but provided everything is well with mama and baby, evidence shows that it is safe to continue a pregnancy into the 42nd week plus 5 whole days!! Statistically speaking, 50% of birthers go into labour spontaneously by the 40+5 mark. The other 50% go into labour spontaneously after that!  


Don't get me wrong, I don't know a single pregnant person who wouldn't cringe at the thought of still being pregnant at almost 43 weeks! Although, knowing that could potentially be how long your body and baby need to be ready for birth might help assuage the common fear that maybe your body won't do what it needs to on its own! 


The Benefits of Letting Your Baby Pick Their "Due Date"


One of the most common questions I get as a Doula when discussing due dates with my clients is this; "How does continuing my pregnancy past 40 weeks benefit my baby if they are basically done developing around the 37th week?" . I really love this question because it gives me the opportunity to "debunk" some of the most common due date myths. 


For starters, your baby is "basically" done developing, but all that means is that all their organs and systems are formed NOT necessarily in full, efficient working order. Its a common misconception that baby is "only gaining weight" in the last weeks of pregnancy, and the truth is that organs like your babys lungs and central nervous system still need time to mature in order to be able to completely take over once your baby is born.


Remember what we said about due dates being more of a guess? Think of it this way. In what you might have estimated is the 37th week, its possible that your baby is only 35 weeks formed/developed or in other words "still not quite ready". At 40 weeks, that same baby would (technically) be 37 weeks formed and have a much higher chance of needing little to no intervention or assistance at birth. Push that date again to 42 weeks (which we know is also a normal and safe gestational period) and baby has now had the "full 40 weeks" to grow and develop. 


Another common concern about going "overdue" is the increased risk of still birth. It might be comforting to know that, while the relative risk does increase slightly, it rises more quickly at 42 weeks to about 1 in 1000 (or 0.01%) for babies who are not growth restricted. This means that while some providers might begin to get nervous after the 41 week mark, with the help of NSTs (no stress tests) and close monitoring by your healthcare provider, it is safe to continue your pregnancy without worrying about stillbirth.


Spontanious Labour Has Its Benefits!


A little known fact; labour begins with a hormonal shift brought on by changes in the placenta! This shift signals the brain to produce the hormones that soften your cervix as well as kick start those practice contractions that thin your cervix (a process crucial for active labour contractions to be effective). Your body also has a chance to build up its natural pain relieving hormones called endorphins (which are 200 times more effective than painkillers like morphine!) Add to that the ability to rest and prepare mentally, not having everything happen all at once after days or weeks of anxiety, and you have a recipe for a better birth experience overall. 


So as a Doula, I think this is WICKED cool and that alone is enough for me to be all for spontaneous labour. But why is this process beneficial over induction? 


The Other Side of The Spontanious Labour vs Induction Coin


Unfortunately, one of the seldom discussed topics in pregnancy books and healthcare providers offices is how induction might impact your labour and birth experience. Under favorable circumstances or for clear medical reasons like IUGR and pre eclampsia, induction works well and can be life saving! However, inductions before a birthers body is "ready", without clear medical reasons, can result in long labours, more painful contractions (not as many endorphins), uterine and fetal over stimulation (which can lead to fetal distress and no rest between contractions), and in some cases, failed induction leading to cesarean section. For more evidence based information on Inductions, visit the Evidence Based Birth website!


Use Your B.R.A.I.N

Like I mentioned before, sometimes inductions really are the best option for so many reasons. That said, its important to be aware of the Benefits, Risks, Alternatives, your Intuition (yes its a valid unit of measure in birth), and to explore what it might be like should you allow labour to begin on its own (what if you do Nothing). We call this using your BRAIN and it is a super useful tool when trying to make these sometimes not so obvious decisions!


If you're in the care of a Dr, they might start asking you if you are thinking about induction around that 40 + 5 days mark. Know that it is your right to refuse should that be something you wish to avoid! If you are considering induction, whatever the reason, don't be afraid to talk to your Midwife, Dr, or Doula about this stuff at any time during your pregnancy! 


Due Month Not Due Date 



Its important to note that some birthers, myself included, DO go into labour spontaneously around the 37-39 week mark! Also, that each and every pregnancy and birther are different! The best way to avoid unnecessary disappointment, anxiety, frustration and subsequent induction is to think of your "due date" as more of a "due month". Babies come when they AND your body are ready! Hang in there! 








Written and Edited (with love) by Rebekkah Traptow 


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