Has someone suggested induction at 39 weeks to you?

It can be so confusing to know what is the right thing to do for you and your baby as there is so much conflicting advice and research.

On one hand, we have the American ARRIVE Trial promoting induction at 39 weeks and on the other, we had the Australian public health initiative that no baby should be born before 39 completed weeks without a clear medical reason.  (You can read more about this in a previous blog HERE )

And then we have the newly released Australian research by Dahlen et al (2021) which looked at the long and short-term outcomes for babies who are induced.

So which research should you believe?

It is really easy to cherry-pick research and choose the studies that you like and don’t like, and this is actually completely within your rights to do.

But it’s not okay for your care provider to cherry-pick research. Their job is to give you all the information you need to make the right decision for you.


Induction at 39 weeks


Let’s start with the ARRIVE trial.


(BTW ARRIVE stands for “A Randomized Trial of Induction Versus Expectant Management” so it is actually a tautology to call it the ARRIVE Trial, but hey!)

When the ARRIVE Trail came out it was hailed by many care providers as the holy grail for this decision-making.

It was designed to see whether elective induction of labor at 39 weeks would result in a “lower risk of a composite outcome of perinatal death or severe neonatal complications than expectant management among low-risk nulliparous women”. (Nulliparous means they hadn’t given birth before.)

“The primary outcome was a composite of perinatal death or severe neonatal complications and consisted of one or more of the following during the antepartum or intrapartum period or during the delivery hospitalization: perinatal death, the need for respiratory support within 72 hours after birth, Apgar score of 3 or less at 5 minutes, hypoxic–ischemic encephalopathy,17 seizure, infection (confirmed sepsis or pneumonia), meconium aspiration syndrome, birth trauma (bone fracture, neurologic injury, or retinal hemorrhage), intracranial or subgaleal hemorrhage, or hypotension requiring vasopressor support.” (Grobman et al 2018)

They also had a secondary outcome which was caesarean sections.

The researchers concluded:

Induction of labor at 39 weeks in low-risk nulliparous women did not result in a significantly lower frequency of a composite adverse perinatal outcome, but it did result in a significantly lower frequency of cesarean delivery”. (Grobman et al 2018)

Now other people have written great blogs on the limitations and biases of the ARRIVE Trial so I won’t go into that. But I highly recommend reading the blogs of Dr. Sarah Buckley and Dr. Sara Wickham on this.

I am going to take the conclusions at face value.

So what the researchers are saying is that inducing a woman at 39 weeks made no difference to those “composite adverse perinatal outcomes” they were looking for but it did lower caesarean section rates.

The actual numbers were: if you were in the induction at 39 weeks group the risk of caesarean section was 18% and if you were in the “expectant management” group the risk of caesarean section was 22%. (In reality, these groups did overlap which is one of the limitations of the study)

So yes, this is statistically significant but actually not that much difference and both those numbers are too high for healthy low-risk women. WHO recommends a caesarean section of 10 – 15% low-risk healthy women.


It’s important to think about that statement it “made no difference to composite adverse perinatal outcomes”.


Different people will interpret this statement differently and suggest different courses of action depending on how they view birth.

Some people will say “it makes no difference so let’s do it”. And other people say “it made no difference so let’s not do it”. 

I am obviously in the “it makes no difference so let’s not do it” group.

But if you add on the fact that it may lower the risk of caesarean sections that may sway some people’s decision.

And this is often how the ARRIVE trial is presented.

Early induction is often recommended to low risk healthy first-time mums to lower their caesarean section risk. 


If this is what your care provider has said, my response to this would be:

“Oh, that’s fantastic that you are concerned about my caesarean section risk. I am so glad we are on the same page. I also really want to avoid a caesarean section so can we discuss the other things that lower my caesarean section risk.” 

“Are you going to suggest that I get a doula?”

“Are you going to follow the ACOG guidelines on the “Safe Prevention of the Primary Cesarean Section?”

I would also be asking the OB… “How’s that going for you?”

I would ask: “Of the healthy, low-risk, first-time mums that you induce how many end up with a caesarean section and how many don’t?” 

Because this is the statistic that matters.

It is important to know what YOUR health providers’ rates are for induction, caesarean section, episiotomies, instrumental deliveries, etc.

Another thing to think about is that the ARRIVE Trial was a randomized controlled trial (RCT). 

An RCT is a great way to research lots and lots of things. However, they rely on very specific conditions which cannot always be replicated in the real world. So it’s important to ask your care provider if they are going to replicate the conditions of the ARRIVE Trail for you.

There are actually lots of variations in induction techniques and so it’s important to know how your care provider performs an induction.



Induction at 39 weeks



This brings me to the study by Dahlen et al (2021) on induction.

Critics of this study will say that it wasn’t an RCT as it was a retrospective study. That is, it looked back to see what had happened. 

This study looked back at 474,645 births over a 16 year period. (The ARRIVE Trial actually only included just over 6000 women although they had initially wanted 50,000… another limitation).

The Dahlen et al study concluded that:

 “IOL Induction of labour) for non-medical reasons was associated with higher birth interventions, particularly in primiparous women, and more adverse maternal, neonatal and child outcomes for most variables assessed. The size of effect varied by parity and gestational age, making these important considerations when informing women about the risks and benefits of IOL (Dahlen et al. 2021)

The study found no reduction in stillbirth rates in this time frame, which is the same as the ARRIVE Trial.

But it did find more birth trauma to babies, more babies needing resuscitation, more babies needing neonatal intensive care, and more babies that were born by induction having ongoing respiratory infections up to the age of 16.

So it did find a difference in those “adverse perinatal outcomes” but also looked at long-term effects, which the ARRIVE Trial didn’t.

I could go onto a discussion about breastfeeding. If you follow Dr. Sarah Buckley’s research it does show that inductions lower breastfeeding success rates. And we know that breastfeeding is protective against respiratory illness and infections in children. But that’s a whole other blog because I think there are lots of confounding factors in this.

I just want to look at the issue of whether an RCT or a retrospective trial is better when studying the impact of inductions.


Is it better to think about what happened in a very controlled environment or what is happening in the real world when making these decisions?

(Here’s where you finally understand the blog title)


induction at 39 weeks

Yesterday I was listening to the ABC Coronacast.  They mentioned a study that suggested the reason for the rare blood clotting disorder after AstraZeneca might be down to the way the vaccine is delivered.

I haven’t been able to find the actual study (and it was only a pre-release paper and not the full study that they were referring to) but I’m going to take Dr. Norman Swan’s word for it.

According to the podcast, the study suggested that, in animal trials, when you give the AstraZeneca vaccination into the bloodstream this is what causes the rare blood clotting disorder. However, if the AstraZeneca vaccination is given into the muscle, as intended, you don’t see the rare blood clotting disorder.

If this turns out to be true, I thought this really shows how in the laboratory or very controlled environments we can get different results from what happens in the real world. 

During the trials of AstraZeneca, the rare blood clotting disorder didn’t show up. This might have been because the numbers are smaller, and it wasn’t until millions of people were vaccinated that the disorder showed up.

But it might also be because in the trials the clinicians were very careful and made sure they were giving all the vaccine into the muscle as it is an intramuscular injection. However in the real world sometimes the person giving the injection might actually get some of the vaccination into the bloodstream by accident.

I don’t want to get into a debate about vaccinations. I have had my first AstraZeneca and will be getting my second dose, although I will be checking whether the nurse checks if she’s hit a blood vessel or not. 

I just thought this was an easy way to explain the difference between controlled research environments and real-world experiences.

As always, as with any intervention, there is a lot to consider.

And as always I suggest using your BRAIN technique when deciding whether or not to agree to an induction. Because it really is all about weighing up the risks and benefits in your unique situation (and then knowing how to reduce the risks if you do need an induction).

Although your care provider does have a responsibility to tell you the risks and benefits if they are suggesting an intervention sometimes, in the real world, you have to do the research for yourself.

Here are a couple of books that I think can really help you with your decision-making process.

Induction at 38 weeksinduction at 39 weeksinduction at 39 weeks

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