One of the most common fears my childbirth class students have is being pressured into an induction because they're pregnant after their due date. Sadly fear is justified for many women: if you're birthing at a hospital, you may be bullied into induction using scare tactics. If you're planning to birth at home or a birth center you may find your midwife's regulations prevent her from attending your birth once you go past a certain date. But what exactly is the problem with going “overdue” – and what exactly does that term mean to you and your baby?
Before we can even begin to discuss going “overdue” or “postdates,” you need to understand exactly what a due date is. Women used to have a general idea of when their baby would come, but being given an exact date was somewhat impossible. Today several different formulas exist to help care providers calculate out an exact “due date” (Naegle's rule being most popular1) – there are also wheels, apps, and other gadgets to figure it out for them.
Unless you became pregnant after an IVF procedure, chances are your due date is calculated based upon the date of your last menstrual period. It's also very common to use ultrasound dating to determine due date, though this has been proven to have a wide margin of error, even in early pregnancy (with about 2 weeks of error on either side)2.
Doctors and even midwives are often doubtful that a woman could know when she conceived (outside of IVF), and many women actually don't know when they conceived. Since ultrasound is available and many women know when their last periods were, those methods are used.
The problem with using the start of the last menstrual period to date a pregnancy is that it assumes ovulation occurred on Day 14 of your cycle, which is not always true. Women can ovulate earlier, later, and for some women, much later. Using the last menstrual period for a woman who ovulated late in her cycle will result in a due date that's too early – and the very real possibility of an iatrogenic preemie (iatrogenic means “doctor caused” – an induction based on an incorrect due date can lead to a premature baby).
Human pregnancy is calculated to be 280 days long because it's rounded off to exactly 40 weeks. In reality studies show that human pregnancy averages 283-284 days (for first-time mamas it averages at about 287 days, or 41 weeks exactly).
Why does that matter? Could 4 days really make a difference?
It makes a huge difference. When calculating pregnancy based on a duration of 280 days, 10% of mamas will go past 42 weeks (the point at which you are technically “overdue”). If you calculate pregnancy to last 284 days, only 1% of women go past 42 weeks! That's a huge difference from just giving a woman 4 extra days over her estimated due date2.
Note that those women are still going past 40 weeks, but very few past 42 weeks, the point at which most doctors insist on induction and many midwives find their regulations prevent them from attending your birth.
We have four apple trees and two pear trees. My children love them! They eagerly await the ripening of the fruit each fall so they can eat apples and pears with abandon. It's inevitable that each fall sees some apples picked too soon. Those apples stay hard and inedible, despite my children's attempts to gnaw at them. Finally apples start to ripen – but not all of them at once. Some are ready early in the season. Others wait until later, when they're the last plump bulges softening just as the air turns really crisp and the leaves assume brilliant colors.
Can you see the similarity between a plump, sweet fruit and a plump, sweet baby?
Our babies don't all “ripen” at the same time – pregnancies vary in length based on mama and on baby. This analogy was first presented in a history of childbirth written by Jacques Gelis, called L'arbre et le Fruit, or “The Tree and the Fruit” in French (unfortunately the official English translation decided to drop the lovely title. Michel Odent brought attention to the very appropriate French title in his own paper titled “The Tree and the Fruit” which we'll revisit later in this article3.
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All of this due date discussion is for two reasons: first to help debunk the accuracy and “gold standard” of a set due date. In fact I agree with Milli Hill's excellent article urging women to follow Kate Middleton's trend of giving only a “due month” (the Duchess is trendy enough that any dress she wears sells out and outdated looks she has the gumption to sport are suddenly all the rage – so why not start a due month craze?)4
But one of the most clear and present dangers of the due date is the enormous pressure it puts on mothers. The end of pregnancy is already tough – you probably felt huge by 30 weeks and by 40 you're sure you're going to pop. You're tired and you ache, and you really, really want to meet the little person who keeps you up at night with his or her kicks. The last few weeks can be challenging in their own way.
Add the pressure of “making the date” and the end of pregnancy can be filled with fear and anxiety instead of excitement and anticipation.
Many mamas want a natural birth and know that induction can and does lead to multiple interventions, including increased risk of cesarean section5. Induced labors are harsh on both moms and babies (especially since some doctors choose to use “pit to distress” regardless of the incredible danger of doing so6)7 and usually result in pain medications that the mother wouldn't have needed if she'd been able to go into labor on her own and give birth unhindered.
Stress and anxiety are part of the response system knows as the “fight for flight” system, which is fueled by adrenaline. Adrenaline does have a place late in labor, when it provides a surge of energy to assist the “fetal ejection reflux” for a mother birthing undisturbed. But its effects before that point are the opposite – it prevents or slows labor since stress, anxiety, and tension are seen as an indication of an outside threat to mother and baby.
The fight or flight system is the antithesis of the “calm and connection” system, which is fueled by the hormone oxytocin (vasopressin also plays a role in it). You're familiar with oxytocin because it is the hormone of labor (it's vital to note that Pitocin/Syntocinon/etc. are synthetic versions of this hormone and do not work the same way in the body – see my article Will the Real Oxytocin Please Stand Up?).
Oxytocin receptors on the uterus, and levels of the hormone, build steadily throughout pregnancy, and high levels of both receptors and the hormone itself are an integral part of the hormonal orchestra that is human labor. Far from being mechanical in nature, labor and birth are controlled by hormones (listen in to this podcast episode for more details on this).
When you're feeling pressured and stress and anxiety build, it shuts off the calm and connection system, which essentially cuts off oxytocin. Instead, adrenaline and its complement of hormones overtake your body and brain, which tell uterus and baby very firmly that labor is not a good idea. It's also why there's a high rate of failure for induction – synthetic hormones have a lot of trouble overcoming your body's own hormones indicating that labor is dangerous to you and baby.
Just the pressure of having to go into labor by a certain date can prevent labor from starting by that date!
The reality of this entire situation is that we cannot look at the “risks” of going overdue without also evaluating the risks of labor induction.
Many doctors pretend that being “postdates” is dangerous to a baby (we'll look at this more in a moment) but induction is perfectly safe. There's no acknowledgment that induction is in and of itself a danger.
When you do acknowledge that inducing labor is dangerous to mother and baby, the decision to induce for postdates becomes balancing the risks vs. benefits – and sometimes it's better to wait, especially if a mother has not reached 42 weeks.
I do want to note that induction is ultimately your choice – when you make an educated decision to have an induction (not based upon scare tactics, convenience, or pressure – aka bullying) – it is fully your choice. Michel Odent makes the argument for personal care and a case-by-case evaluation for each mother and baby in his article “The Tree and the Fruit,” stating that individualized care is what makes a difference for mothers and babies3. There is no one right or wrong answer, just the responsibility (for both your care provider and you as a parent and client) to examine the true risks and benefits of each choice. Many care providers, both doctors and midwives, oppose routine induction for postdates women.11
It's dangerous to pretend that induction is not dangerous. One study proudly noted that induction resulted in fewer post-term fetal deaths, which giving a quick mention to “somewhat increased maternal mortality.”2 What exactly does a statement like that mean? Since “maternal mortality” means that mothers are dying, is that truly an acceptable outcome? I think not. Again, it's important to examine risks versus benefits for all choices and make what's right for you. Click here for more on induction.
I also want to note that “natural” induction is still induction, and should be treated as such – click here for more information.
With that, lets look at the risks of going “overdue.”
It is important to note that when medical literature discusses risks of going “post term” or “postdates” it is referring to going over 42 weeks pregnant. Though many doctors jump at induction the moment you hit 40 weeks + 1 day, the normal variation of human pregnancy means that most women will have their babies before 42 weeks (especially if 42 weeks is considered 284 days into pregnancy rather than 280, as I discussed above).
If you're being pressured to induce before you reach 42 weeks, bring evidence to your care provider that the risks of being past your baby's due date to not justify the risk of induction at that point. And, as I also covered above, the accuracy of dating your pregnancy (unless you used IVF to conceive), is subject to error. In other words, you due date is probably not exactly correct – even if (perhaps especially if) ultrasound dating was used early in pregnancy – and certainly not in later pregnancy.
The placenta is usually cited as being the problem for “overdue” babies. However, research shows there's no evidence that the placenta begins to fail in late pregnancy at any rate greater than any other fetal organ8. The placenta does grow and change (just as your baby does), but it shows no evidence of being unable to supply the baby with proper nutrients.
In fact, one of the two common complications with postdates pregnancy is macrosomia, which means that baby is very large. This “complication” suggests that the placenta keeps working quite well – well enough to grow a large baby! The other issue is often oligohydramnios, which means low amniotic fluid. Amniotic fluid is produced independently of the placenta, and it is theorized that the low volume of fluid may cause blood flow issues between placenta and baby (not the other way around, with the placenta causing the fluid problems). Also note that ultrasound measurements of amniotic fluid are considered rather inaccurate.9 It's thought that these complications may contribute to the increased rate of stillbirth past 42 weeks.
Just as any organ can fail at any point during gestation or life, it is possible for the placenta to fail at any point during pregnancy.10 It's also important to note that babies born postdates have a higher rate of congenital abnormalities that could lead to placental problems.
This high rate of abnormalities also indicates something else… remember, congenital abnormalities are problems that occurred in the baby as he or she developed. Postdates babies have more than “term” babies because the developmental problems cause the baby to go postdates. Again, it is not the other way around.2. A baby with congenital abnormalities is also more likely to be stillborn and it is the developmental problems that contribute to that.
Routine monitoring has also been shown to be of little value for predicting problems with babies.2 Watchful waiting is a good option, as obstetrician Michel Odent notes in the article I discussed above. Older studies showed more babies died in a “watchful waiting groups” – but again, these studies were older studies, and they also tracked women in 3rd world clinics – not women in modern countries. Prenatal care, awareness of what it takes to grow a healthy baby, and general understanding of pregnancy and birth have changed a lot in the past several decades – and things are certainly different for educated women in modern countries than they are in poor and famine-ridden areas of 3rd world countries.12
It's also true that rates of stillbirth as a result of going “postdates” vary between the United States and Europe2, which indicates that there is probably more going on than just a mother going past her due date by a couple of weeks.
Each situation deserves individual care – and we know that a healthy, well-nourished mother has a placenta that can function well even after 41 weeks, and careful assessment after 42 weeks with informed choices leads to the best outcomes for mothers and babies.
So we've talked about some issues to think about seriously if you're going past your due date. Remember though, especially if you are a first-time mama who is getting on past her due date (I can relate – I went to 41 weeks, 3 days with my first!), that going past your due date is pretty normal. They're generally a rough estimation, not set in stone. Keep those things in mind and make the decisions that you feel are right for you and your baby – chances are your instincts are right on. Here are some things to consider as you wait on your baby:
I carry on about it a lot because, well, people just don't realize just how important hormones are to birthing. The hormonal goodness doesn't stop when you finally get done with being a gawky teenager. They're important throughout your life, and especially to your fertility, pregnancy, and birthing. Oxytocin helps you relax and enjoy your pregnancy, and it primes your body for labor to begin. Do things that increase your comfort and relaxation and you may help encourage labor to get going.
Go out for lunch, fold baby clothes, meander around the mall. Turn off your phone. Unplug from Facebook. Just enjoy these last few days. Take long baths. Really enjoy.
In reality, an extra week or two is not very much – it will be over in an instant and you'll be wrapped up in the craziness that is caring for a newborn… and 18 years of one long adventure helping your little one fly the nest 😉
Talk to your and let baby know that you're ready for birth. And while you're at it, make sure you are. Is there anxiety or stress going on? Fears that you've pushed to the back of your mind? Are there relationship issues that you're worried about?
All of those things are normal – and sometimes the mind is very powerful. Take the time to address those things so you can feel confident about going into birth.
Let your baby know that you're really ready to meet him or her. Spend some time picturing a beautiful labor and birthing. Fold and re-fold baby clothes, gather birth supplies, and get everything just perfect. All of that communicates in a powerful way, and thoughts do influence our reality (and our hormones!)
I could give you a long list of things to try, like walking up and down stairs, making love, cleaning your floors, etc. But what you really need is to relax and pamper yourself and your baby. Get educated and make peace with the choices you make – don't let somebody push you around (but it's fine to carefully consider advice).
I encourage my students to read all that they can about the dangers and effects of induction, and to examine the realities of the length of pregnancy. Remember that we still don't understand exactly what causes labor to begin or progress, and there is much that happens that we can neither see nor even imagine. It may be that your baby needs longer, that you need longer, and that many unseen changes and processes are happening13. Know that in most cases, your baby knows the perfect time to be born – and will be born then.
Enjoy these last days, gentle mother, because they are fleeting. Enjoy an ice cream and your baby's kicks – you will miss them when they're gone 🙂
Don't forget your natural birth cheat sheet!
1. http://www.austincc.edu/adnlev3/assessment_of_normal_pregnancy/naegeles_rule.htm (accessed 12/07/14)
2. Cohain, Judy “The Surprising Lack of Evidence for Postdate Birth Induction” http://www.greenmedinfo.com/blog/surprising-lack-evidence-postdate-birth-induction (accessed 12/07/14)
3. Odent, Michel “The Tree and the Fruit: Routine versus Selective Strategies in Postmaturity” Issue 72. Winter 2004. Midwifery Today
4. Milli Hill “Why Pregnant Women Should Follow Kate's Trend of a Due Month” (accessed 12/07/14)
5. http://journals.lww.com/greenjournal/Abstract/2010/07000/Labor_Induction_and_the_Risk_of_a_Cesarean.8.aspx (accessed 12/07/14)
6. http://nursingbirth.com/2009/07/08/%E2%80%9Cpit-to-distress%E2%80%9D-a-disturbing-reality/ (accessed 12/07/14)
7. http://www.drugs.com/pro/pitocin.html (accessed 12/07/14) – please note the incredible list of warnings of possible effects and reactions (including uterine rupture and fetal seizures and brain damage) from induction/augmentation with Pitocin
8. Fox, Harold. “Aging of the Placenta.” Archives of Disease in Childhood. 1997;77;F165-F170