There’s so much to say about the new MANA study by Cheyney et al. that I’ll be covering it in several posts.
Earlier today I gave a brief overview of the results (Homebirth midwives reveal death rate 450% higher than hospital birth, announce that it shows homebirth is safe). In this post, I’d like to address the timing of publication of this study.
Specifically, if the results of the study really show that homebirth is safe, why did MANA wait 5 years to publish them?
The answer is that the study doesn’t show that homebirth is safe and Cheyney et al. are fully aware of that fact. They didn’t want to publish the results, but they were pressured into it, and are now trying to convince people that a death rate more than 5.5 X higher than comparable risk hospital birth is “safe.”
Their reluctance to publish damaging data is known in technical terms as publication bias.
MANA did not pioneer this type of publication bias. That was done by the drug companies. They have a vested interest in publishing studies that promote the use of their medications and failing to publish study results that call the efficacy or safety of their drugs into question. The classic case of this type of publication bias is Vioxx. Merck had commissioned and paid for a study that showed Vioxx had dangerous side effects. Merck did not publish these results and did not share them with physicians.
How do we know that the failure to publish the MANA statistics for the past 5 years was publication bias? Since we are not privy to the thought processes of the investigators, we can only tell by process of elimination.
The failure to publish was not due to the lack of availability of the statistics: As early as the summer of 2006, MANA was offering the statistics up through the previous year … but only to people vetted by MANA who were willing to sign a non-disclosure agreement promising not to let anyone else see the results.
The failure to publish the results was not due to a need to withhold the data pending journal publication: As far back as April 2011, MANA was publicly boasting about the 5% C-section rate in this cohort. But they wouldn’t tell anyone how many babies died to achieve that C-section rate.
The failure to publish was not due to any need to publish them in the context of research: I had been pounding MANA on my blog about the failure to release their death rate since 2006, but it wasn’t until November 2011 that I gained a large national readership with my piece in Time.com. The executives at MANA were so alarmed that they felt the need to respond publicly.MANA executives implied that statistics could only be released in the context of research. That is completely untrue. Every state and the US government releases annual statistics on the number of births and the number of neonatal deaths (not to mention a myriad of other health issues). This information is publicly available to anyone for free through the CDC. MANA could have released its data to the public for free in the same form as the CDC data. There was nothing preventing them from doing this beside their unwillingness to reveal the numbers.
MANA has been quite creative in fabricating new excuses: In October 2013, Melissa Cheyney claimed that MANA could not release its statistics without IRB approval. That’s not true. First, MANA itself has published almost all the data from the database EXCEPT the death rates. Second, while IRB approval could be required for publications based on the data, IRB approval is not required to read and review the data.
It’s difficult to conclude that MANA had any other reason for holding back the statistics besides the fact that they KNOW this data shows that homebirth has a dramatically increased risk of death.
Why did they suddenly relent and publish the data?
I suspect that there were two reasons.
First, increased public pressure such as the Change.org petition demanding the release of the data.
Second, their failure to publish the death rates had led everyone to the obvious conclusion that the death rates were hideous. Therefore, I suspect that they gambled that they had nothing to lose by publishing the data and then pretending it shows something different than what it actually shows. Everyone already knew that the death rates were horrible so the only way to combat that impression was to publish them and slice and dice the data in a million ways to confuse readers, while simultaneously misrepresenting what the death rates mean.
Simply put, MANA refused to release the death rates until now, because they know and have always known that these death rates are horrific. If the death rates were even close to demonstrating safety, MANA would have been shouting them from the roof tops since 2006, when the first analysis was complete. Instead they waited until they were pressure to release the data and are now hoping to hoodwink their followers by declaring that a 450% increased risk of death at homebirth is an indication of safety.
The only thing that remains to be seen is whether their followers are gullible enough to ignore the evidence of their own eyes in favor of the deliberately misleading spin put forth by MANA.
If any homebirth advocates have another remotely plausible reason why MANA withheld data of “safety” for the past 5 years, while publicly releasing every the C-section rate, the intervention rate, the transfer rate, etc. etc. etc., I’d love to hear it … but I’m not holding my breath because I could turn mighty blue.