Sunday, December 10, 2006

Response from Lamaze blog

A response was posted this evening to my comment on the Giving Birth With Confidence blog. The response addresses only 1 of the 3 papers that I quoted, but it is the most important paper.

To recap my original comment:
...Johnson and Daviss' 2005 BMJ study, Outcomes of planned home births with certified professional midwives: large prospective study in North America which showed a neonatal death rate of 2/1000. The actual control group is low risk white women who delivered in the hospital that year. The neonatal death rate in that group was only 1/1000.

Initially I was quite suprised that Ken Johnson, a professional statistician made such a serious error. Then I learned that Dr. Johnson held another position: head of the MANA (Midwives Alliance of North America) Statistics and Research Committee. In fact, as you undoubtedly know, Johnson and Daviss have been passionate homebirth advocates for many years, long before they embarked on the study. Furthermore, the study was not funded by an academic institution or a government agency. Rather, it was funded by Foundation for the Advancement of Midwifery, a homebirth advocacy group. The study itself was commissioned by NARM (the North American Registry of Midwives).

So using money from a homebirth advocacy group, NARM, a homebirth advocacy group, hired homebirth advocates Johnson and Daviss to produce a study on homebirth. The conclusion appears to be predetermined. When an industry hires known allies to do a study about that industry, the results are going to be favorable.
The response posted by Judith Lothian is:
It is important to know that the difference between 1/1000 and 2/1000 neonatal deaths in the Johnson and Daviss 2005 study is NOT statistically significant. That means that we can not claim that more babies will die at home births. That’s what the research means. Pure and simple. And that finding contributes to the larger finding that home birth…planned for healthy, low risk women, is as safe if not safer than birth in the hospital.
Here is the response that I submitted, which is now awaiting moderation:
How do we know that it is not statistically significant? What statistical test did you use to make that determination? That particular statistical analysis was not done in the actual study, since Johnson and Davis used the wrong group as a control, and then claimed that the results from their study were the same as the results in the erroneous control group. Why did they bother using the WRONG control group, a group compiled from out of date homebirth studies, and a group with a higher neonatal mortality rate, except to avoid showing that the rate of neonatal death in the homebirth group was actually double the rate in the hospital group?

We are left with only two choices: They deliberately used the wrong control group to hide the fact that the death rate in the homebirth group is DOUBLE the neonatal death rate for babies of low risk white women who delivered in the same year.

or: They actually don't know how to figure out the appropriate control group. If they do not know even the most basic principles of statistical analysis, then the entire study, its analysis and its conclusions are called into question.

Either way, the results are wrong, and therefore, the paper does NOT show that homebirth is as safe as hospital birth.
Interestingly, there was no attempt to deny that the control group used in the study was an inappropriate control group. The essence of Lothian's response is that it doesn't matter if the control group is inapproriate. I think it matters a great deal. The bottom line remains that there is NO scientific evidence that shows homebirth to be as safe as hospital birth.

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