A(nother) Critique of the Wax Paper

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By ANaturalAdvocate

The Wax paper is has been all over the news recently. Not only have many discussed the paper before (see here, here, here, here, and, of course, here), but the American Journal of Obstetrics & Gynecology just posted a number of letters critical of the study, all of which are available on their website. While the editors, and a panel convened especially to review the paper at hand and available criticisms, did not feel a retraction was necessary, they did mention several concerns with the study and concluded that, “It is clear that we need more rigorous and better designed research on this important safety issue of home birth, given the many confounding factors.”

How rigorous that research might need to be is the subject of a recent Medscape article entitled “Planned Home vs Hospital Birth: A Meta-Analysis Gone Wrong.” According to the authors, there were many problems with the Wax paper and “it is incomprehensible that medical society opinion can be formulated on research that does not hold to the most basic standards of methodological rigor.”

While much of the information has been mentioned before, such as in the very comprehensive article by Gail Hart in Midwifery Today, this new critique by Michal, et al., is a much more detailed look at the methodology and analysis of the Wax paper.

Among their concerns?

  • The authors of the Wax paper included studies that did not meet the definitions of the meta-analysis itself.
  • Numerical errors significant enough that the conclusions drawn in the meta-analysis were unlikely to be accurate.
  • Instead of using widely-accepted and professional statistics software, the meta-analysis used a university class spreadsheet containing so many errors (admitted by the authors of the spreadsheet) that all of the numerical results were incorrect. Sometimes this error was significant enough that the answer reported was opposite of what the real statistics said. 
  • The meta-analysis used contradictory language in the abstract and the body of the paper itself. As many readers only can or will read the abstract of the paper, it is important that it accurately reflect the body of the paper itself.

Michal, et al., do not re-analyze the data, and do not take a position on home birth and home birth safety. However, they do recognize the “emotionally charged” atmosphere surrounding the home birth question, and state that, “Reliable information is required to allow productive debate and informed decisions.”

While a randomized study is unlikely to occur, and would be highly unwise for a number of reasons, it seems that by now accurate and appropriate analysis of the data available should not be the problem it seems to be. With home birth rates increasing, and even The Economist stepping into the fray, the need for transparent and rigorous studies is greater than ever.


The author very kindly thanks Christie Babinski for her assistance.