The “Due Date” and what happens if you pass it

Written by Amber Baumberger

You find out you are pregnant, then you are given your Estimated Due Date (EDD), which is equivalent to 40 weeks of pregnancy. Everyone asks when you are due, so of course you tell all your family and friends the baby will be born around this date. You have in your head that this is the date you will have your baby. As the date comes and goes and you are still pregnant, you start to wonder:

What is wrong with my body? Will I ever give birth? Is the baby okay? They will probably need to help me give birth to my baby.

Then family and friends who are eagerly awaiting news message you and ask if the baby has arrived yet which adds to your anxiety.

You also get medical professionals reinforcing the idea that something is wrong when they request more ultrasounds, lots of monitoring at the hospital and schedule your induction for “post dates” for the health of your baby.

This scenario is unfortunately the reality of so many pregnant women waiting for the arrival of their baby. The reality is that only around 4% of women give birth on their EDD and only 50% of women will have given birth by 40 weeks+5 days (Evidence-Based Birth). This leaves roughly 50% of women believing they are “overdue” and getting downhearted and anxious about their baby not coming yet.

K’s Story

Baby born spontaneously at home at 41 weeks, 2 days.

Once reaching 40 weeks, an induction was booked in. It felt like a ticking time bomb waiting for intervention to begin and a sense of fear kicked in because of that. There was a fear of losing my choice of a publicly funded homebirth if the pregnancy passed 42 weeks. The language used by medical staff to talk about all these things fuelled the fear I felt as well. The communication style also made it feel like they were talking about what they would be doing to my body if it didn’t go into labour by a specific date, rather than it being a choice. It made me feel a bit broken and question why it wasn’t happening the way it should for me.

A’s Story

Baby born after induction and emergency c-section at 41 weeks, 3 days.

Once reaching 40 weeks, I had an appointment at the hospital where they informed me that I should have been scheduled for an induction already because my baby was measuring big. Since they hadn’t already booked my induction, the earliest spot available was 41 weeks and 2 days. I was told because of the baby's size, I would need to phone the hospital everyday to see if a spot had come available. They explained they were concerned about complications of the baby getting too big and I was booked in for monitoring appointments every few days. They did a stretch and sweep at the 40 week appointment and told me to try to bring labour on myself because “the sooner a big baby is born, the better.” The next days came with a lot of stress and fear while I tried to do all the things to bring on labour. I went into the induction, feeling like my body was not doing the right thing and with the belief in my head that since I wasn’t induced at 40 weeks, my baby would be too big to be born vaginally.

Where does the EDD come from?

The calculations to work out the EDD were created in the 1700’s and are not how pregnancy length has always been measured. Traditionally, pregnancy was tracked with lunar cycles. Pregnancy lasted for 10 moon cycles. The completion of these ten moon cycles is equivalent to approximately 42 weeks. It was common knowledge that the women would give birth some time in the tenth moon cycle, up to around 42 weeks (Reed, 2021). If it was known and observed for so long that pregnancy lasted for around 42 weeks, why the shift to put emphasis on this due date of 40 weeks in the 1700s?

It is also important to note that some women simply gestate longer than others. This longer gestation period is often down to genetics and by looking at your mother, sister and baby’s biological father’s family history, you can get an indication if you are likely to have a longer pregnancy. In these cases, the pregnancy can continue into week 42 and 43 with no negative impact on mother or baby. There are also other factors that might mean you carry the baby longer, such as your weight, baby’s size, first pregnancy, high stress at the end of pregnancy etc (Evidence-Based Birth).

Risks of going over 40 weeks

From looking at different studies, it has been concluded that the risks of certain conditions and complications developing with mother and baby increase as you go past 40 weeks. These include infection, problems with the placenta, having an assisted delivery, NICU admission, large baby, among others. All of the risks and the statistics can be found on Evidence-Based Birth.

One of the big worries that get discussed with women going over 40 weeks is the risk of stillbirth increasing. The causes of stillbirth are often unknown. However, there are risk factors that may increase a woman’s chance of stillbirth (Raising Children Network). Recent research has shown that an aging placenta can be a reason for a stillbirth to occur. If aging of the placenta occurs, it often takes place after 41 weeks of pregnancy, which is one of the reasons why once a woman enters the 42nd week of her pregnancy, it is considered more risky or dangerous by many care providers. When the placenta ages, it can’t keep up with the demand of the baby and ultimately the baby does not get what they need to sustain life and passes away (Hunter Medical Research Institute). The risk of the baby dying due to deterioration of the placenta is higher after 42 weeks, but it does not mean that the absolute risk of this happening is high. Individual circumstances may increase or decrease the risks too.

placenta, healthy placenta, organ — *Healthy placenta*

The hospital is a technocratic system where the focus is on avoiding death at all costs. This is of course something people would like to avoid, but what it doesn't factor in is what all the extra testing and interventions do to the mother and baby. While all the extra scans, testing, appointments and early induction can reduce stillbirth rate, we don’t see the numbers of the negative effects of unwanted testing, scans and induction. If these mothers, who did not want extra monitoring and inductions booked, had been left alone and not told to go into hospital for testing every couple of days, they could have given birth before 42 weeks on their own anyway. The impact on the mother’s mental health, belief in her body, and ultimately high levels of stress at the end of pregnancy because of all these extra appointments and testing can delay the onset of labour and exacerbate the problem.

Induction to avoid prolonged pregnancy

When you reach 40 weeks pregnant, standard protocol is to book in the induction at that appointment for roughly 41+3 weeks pregnant to reduce the risk of perinatal death and complications associated with a big baby. Many women do not want this induction but it gets booked “just in case”. Then there is the extra monitoring and offering of stretch and sweep to get things moving before the induction date. Studies do show that inducing labour before 42 weeks reduces the chance of perinatal death from 3:1000 to 1:1000 (Reed, 2021). What this fails to look at are the risks to mother and baby of being induced in the first place as opposed to going into labour spontaneously. The NICE guidelines state “while the risk of perinatal mortality, NICU admission, and caesarean birth increases over time with a prolonged pregnancy, the absolute risk remains low.”

This protocol puts the idea into many women’s heads that their body is not doing what it should be doing and means a lot of women agree to extra appointments, scans and having the induction booked when that’s not actually what they want to do. Once the induction is booked, women are on the clock and then there is the stress of how she can go into labour before the induction date. The NICE guidelines also emphasise that it is necessary for women to be fully aware of all the risks and benefits of inducing at 41+ weeks vs waiting for spontaneous labour to allow for true informed consent.

induction, postdates, pregnancy, labour — *CTG monitoring during induction*

What happens after 42 weeks?

Once a woman enters the 42nd week of pregnancy, it is considered a ‘prolonged pregnancy’ From this date, in the public system, the woman is no longer accepted into Family Birthing Centre or Community Midwifery Program and ‘must’ give birth in the hospital under a specialist team because she is now considered ‘high risk’ (Government of WA). However, this is not the case for private midwives who can use their own judgment as to whether they will support a birth at over 42 weeks gestation (Homebirth Australia).

The NICE guidelines state that women would usually need to give birth under obstetric care for a prolonged pregnancy because they recommend continuous monitoring (due to risks associated with a big baby and chance of stillbirth). In a healthy woman, there is no evidence for continuous fetal monitoring affecting outcomes. However, it does impact how she births and where she can birth. The recommendation of continuous fetal monitoring, simply is a recommendation, based on knowledge and experience to manage the increased risks. The guidelines state that the woman should be given the option for monitoring and told all the benefits and implications of the monitoring so she can make a decision. However, due to the policies in place with the public system, she would need to give birth in hospital.

At the end of the day

Informed consent is important. It means that a woman is made aware of the risks and benefits of all the options available to her, including doing nothing. When she knows what to look out for herself and more importantly is encouraged to connect to her baby and learn their movements, she knows when she needs extra checks or assistance. Medical intervention in pregnancy does not need to be traumatic or stressful. When it is intentionally chosen by the woman and used to support her decisions, rather than having decisions taken away, it can be a positive experience (Bell, 2024).