File Hannah Dahlen’s latest paper under D for Duh!

Three wooden blocks spelling "Duh!".

What if I told you that people who take insulin are more likely to develop blindness than those who don’t?


Blindness is a known complication of diabetes and insulin is a treatment for diabetes. It’s the diabetes that causes blindness NOT the insulin.

The real issue is whether diabetics who take insulin are more or less likely to develop serious complications than those who don’t.

How about if I told you that people who have heart transplants have a shorter lifespan than those who don’t?

The critical issue, which the authors did not bother to address, is whether those who got the interventions did better than if they hadn’t gotten them.


If you need a heart transplant you are very sick indeed and your other organs might have been damaged by your weak heart before you became got an available organ. It’s the underlying disease that created the need for the transplant that caused the shorter lifespan NOT the transplant itself.

The real issue is whether those who need heart transplants and ultimately get one live longer than those who don’t.

Along comes Hannah Dahlen to tell us that those babies who need childbirth interventions have more bad outcomes than those who don’t.


But that’s not how Dahlen spins it.

On The Conversation, Dahlen writes.

Medical and surgical intervention during birth continues to rise in much of the world. Nearly one in three women who give birth in Australia have a caesarean section and around 50% have their labour induced and/or augmented (sped up with synthetic hormones).

Our new research, published today in the journal Birth, found babies born via medical or surgical intervention were at increased risk of health problems. These include short-term concerns such as jaundice and feeding problems, and longer-term illnesses such as diabetes, respiratory infections and eczema.

You remember the “journal” Birth, right? That’s the one owned by Lamaze International, the organization that makes its money by convincing women that childbirth interventions are bad. Although they routinely charge $38 dollars for 24 hour access to one article, they’ve conveniently made this one free so everyone can learn about the “dangers” of childbirth interventions.

But childbirth interventions are like insulin or heart transplants; the people who need them will often die without them. The real issue is whether those who need childbirth interventions do better or worse without them.

How did Dahlen and colleagues answer that question? They didn’t even bother.

In a paper of 11 pages in length, buried near the very end, is the single most important sentence in the paper:

…[W]e were unable to control for confounding by indication since the underlying reasons for the provided medical and operative birth interventions were unknown.

And that renders the results of this study 100% meaningless!

But that doesn’t stop Dahlen.

We found:

Babies who experienced an instrumental birth (forceps or vacuum) following induction or augmentation had the highest risk of jaundice and feeding problems needing treatment in the first 28 days

Babies born by caesarean section had higher rates of being cold and needing treatment in the hospital for this compared to babies born via vaginal birth

Children born by emergency caesarean section had the highest rates of metabolic disorders (such as diabetes and obesity) by five years of age

Rates of respiratory infections, such as pneumonia and bronchitis, metabolic disorders, and eczema were higher among children who experienced any form of birth intervention than those born vaginally.

Wow, they really had to slice and dice the data to make up something ominous.

And even Dahlen acknowledges that most of those results are entirely expected:

Forceps and vacuum birth, for instance, can cause bleeding and bruising in the baby’s scalp. These blood cells break down, releasing bilirubin that causes the skin to look yellow, which signals jaundice.

Babies born by caesarean section are more likely to be cold because the operating theatre is cold. Despite recommendations for the baby to be placed on the mother’s chest as soon as possible, this doesn’t always happen.

What she should have pointed out — but deliberately did not — is that babies born by C-section are often rescued from medical problems like fetal distress which necessitated treatment in the NICU.

What she should have pointed out — but deliberately did not — is that children born by emergency C-section are more likely to have mothers who are diabetic and obese (both of which are therefore more likely in offspring).

What she should have pointed out — but deliberately did not — is that large data sets are vulnerable to p-hacking.

Researchers look for statistically significant differences between two groups. Then they announce them as “findings” without acknowledging that any large dataset looking at multiple outcomes is bound to have random statistically significant differences that are coincidental and don’t represent real outcomes. Indeed, by definition using a p value of less than 0.001 means that almost 0.1% of the differences that appears to be statistically significant are actually due to chance and don’t represent a real finding at all.

How do you guard against p-hacking? The most important way is to recognize that it is always a possibility when analyzing large datasets; in other words, it is wrong to conclude that every statistically significant result in such an analysis is a real result.

Despite having found found NOTHING AT ALL, Dahlen proceeds to spin elaborate theories about her “findings.”

Reasons for the increased risk of longer-term problems are much less clear, but there are a couple of interesting hypotheses.

The first key theory is based on epigenentics: that life events affect how genes function and are passed on to the next generation.

Labor and birth exert a positive form of stress on the fetus, which impacts on the genes responsible for fighting off bugs, weight regulation and suppressing tumours. Too little stress (no labour and elective caesarean section) or too much stress (induced/augmented labour and instrumental birth) could impact the expression of these genes.

The second key theory is the extended hygiene hypothesis. This suggests that vaginal birth provides an important opportunity to pass gut bacteria from mother to baby to produce a healthy microbiome and protect us from illness.

If we have an unhealthy microbiome, we may be more vulnerable to infections, allergies, diabetes and obesity.

Dahlen doesn’t even asked the single most critical question.

Just as the key question for insulin and heart transplants is whether those who received it did better than they would have if they hadn’t received it, the key question for birth interventions is whether those who received them did better than they would have if they hadn’t received them.

Dahlen didn’t bother to look because that would have produced entirely different results than the demonization of interventions that drives contemporary midwifery theory.

File Dahlen’s latest paper under D for “Duh!” as well as D for “demonization.” It is not science; it’s ideology masquerading as science and it isn’t even very well disguised.