Homebirth and optimistic bias

Consider the following situations:

1. Homebirth advocate Rixa Freeze proudly relates the near death of her baby at an (oops!) unassisted homebirth:

Soon after the birth, Inga lost muscle tone and color. I quickly realized that I needed to perform mouth-to-mouth. Fortunately, I became certified in neonatal resuscitation several years ago, so I knew what to do. It was tricky getting the angle right, since the cord was short. I gave her five breaths. After each breath, she coughed and perked up a bit more.

Rixa herself was spinning the near disaster as though it was nothing serious and that she had educated herself to handle the situation calmly and with ease. Rixa seems to imply that what happened to Inga is the worst emergency that can happen at homebirth and all you have to do is take a neonatal resuscitation course and you will be adequately prepared to save your baby’s life.

2. The mother of baby Florence, discussed in yesterday’s post (What were they thinking?) whose baby is in the NICU due to the irresponsible actions of the patient and her midwives. The mother is obsessed with the issue of whether the baby is getting breast milk and has completely ignored the more pressing issues of the baby’s survival and brain function.

3. A pathetically ignorant homebirth blogger currently treating us to the series The safety of home birth and why I chose it twice :

I’m not going to pretend that my first birth was all roses. My first baby was born with a low Apgar score. She wasn’t breathing because the cord was wrapped around her neck (which happens in 25% of births), and it took my experienced midwife several minutes of CPR to get her breathing. But I wasn’t frantic. Do you know why? Because the cord hadn’t been cut, and I knew that she was still getting the oxygen she needed. She would be fine because she was getting oxygen the same way she had for the previous 9 months. Now in a hospital, it’s pretty likely that cord would have been cut right away and my baby rushed away . Then I would have had cause to worry. Then my beautiful baby girl may have suffered brain damage from lack of oxygen.

These three homebirth advocates ended up in desperate situations because they suffer from “optimistic bias.” Optimistic bias also leads them to minimize the significance of major complications, and give outsize attention to small risks while ignoring large one.

What is optimistic bias? In an editorial in the August 2011 issue of the Journal of Clinical Nursing entitled The implications of the optimistic bias for nursing and health, Aja Murray explains the phenomenon.

The tendency to believe that negative events are less likely and positive events more likely to happen to oneself than to others is known as the optimistic bias. In a health setting, this can manifest as a serious underestimation of health risk. Biases can be highly resistant to change and this can contribute to an unwillingness to take preventative or restorative action…

That describes homebirth advocates perfectly. They grossly underestimate the risk of pregnancy complications and therefore they reflexively refuse to take any preventive action (prenatal tests, antibiotics for group B strep, C-section for breech, etc.) and even when complications do occur, as they inevitably occur in exact same proportions as the rest of the population, they delay and even refuse lifesaving and neonatal brain sparing treatment. And when bad outcomes occur, they dismiss their significance as minor.

Homebirth advocates don’t merely fall prey to optimistic bias, they actively promote it among themselves and proselytize optimistic bias to everyone else. They justify this optimistic bias by claiming that they aren’t going to develop pregnancy complications because they practice “good nutrition,” they exercise and they employ bizarre alternative treatments like “cranio-sacral therapy,” even though there is precisely zero evidence that these have any impact on the development and severity of pregnancy complications.

But optimistic bias is not a virtue, it is a danger. As Murray explains:

Optimistically biased judgements can cause individuals to underestimate their vulnerability to a wide range of health conditions, including cancer, cardiac, substance abuse and HIV. It is also associated with greater risk of health-related factors such as high cholesterol.

… Overall, however, the evidence suggests that having an optimistic bias is more likely to have a net negative impact on health.

That is certainly the case for homebirth advocates. The only people who appear to be unaware of the fact that homebirth increases the risk of perinatal death are homebirth advocates.

Why do they engage in optimistic bias?

Evidence suggests that both motivational factors, which serve to preserve self-esteem and avoid anxiety, and non-motivational factors, such as errors in comparative judgements, interact to produce and maintain an optimistic bias . Thus, any intervention must target both. Most interventions to date have, however, focused on non-motivational aspects of optimistic biases. … [Attempts] to reduce participant reliance on inaccurate information by providing information about their relevant risk factors and highlighting aspects of the information that would be expected to produce unfavourable comparative judgements. These interventions, however, failed to produce a consistent reduction in bias…

… [O]ptimistic bias … encourages attitudes and behaviour which minimise awareness of undesirable and anxiety-provoking information which may threaten a positive self-image… [I]ndividuals who express an optimistic bias are less likely to be aware of risks to their health, less open to novel health-relevant information and more susceptible to believing health myths. Indeed a significant predictor of an individual’s health relevant behaviour is his/her feelings about health risk which can outweigh a rational evaluation of risk.

Does this apply to homebirth advocates?

✓ Preservation of self esteem
✓ Avoiding anxiety
✓ Errors in comparative judgment
✓ Resistance to scientific evidence
✓ Belief in health myths

It most certainly does!


If the [health risk] is perceived to be positive and controllable, then individuals are likely to be more biased in their comparative judgments than if the dimension is positive but uncontrollable. This implies that patients affected by health problems that are amenable to protective behaviour, such as taking regular exercise, are most likely to underestimate their health risk. Ironically, those for whom there is the most scope for health improvement are likely to be the least motivated to take steps to make these improvements.

Homebirth advocates insist that they can control their risk of pregnancy complications. Therefore, they dramatically underestimate those risks and refuse to take the steps most likely to reduce the risks, including conventional antepartum care, prenatal tests, and most importantly, delivery in a hospital.

Murray sees a role for health providers in reducing optimistic bias. Unfortunately, in homebirth advocacy, the providers (midwives) suffer as much or more from the same optimistic bias, and for the same reasons. Homebirth midwifery is basically a hobby designed to boost the self-esteem of poorly educated homebirth midwives. They are resistant to scientific evidence since they have little idea what the scientific evidence shows, they are incapable of making comparative judgments of risk and they believe in health myths.

Optimistic bias is notoriously resistant to evidence since it is not about evidence; it is about the self-esteem of those who ignore health risks. That is certainly the case in homebirth advocacy. Of course health care providers should continue to explain the health risks, but they might consider going a step further and addressing the underlying issue. A frank discussion of the way that all people, not just homebirth advocates, have a tendency to fool themselves about risk will shift the focus away from their purported “knowledge” to their motivations.

Just like smokers minimize the risk of lung cancer to themselves, and alcoholic minimize the impact of alcohol abuse on their health, homebirth advocates minimize the risk of pregnancy complications, both the risk that they will occur and the consequences of those complications. In all three cases it is not because the smokers, alcoholics or homebirth advocates are more “educated.” It’s just that they are better at kidding themselves.