- PROBLEM: How to evaluate immunological therapy advocated for recurrent spontaneous abortion and implantation failure. I was invited to comment on the opinion article of Chaouat (AJRI December 2003). METHODS: A critical examination of key beliefs and application of the principles of evidence and logic utilizing current data. RESULTS AND CONCLUSIONS: Although rationale has no bearing on efficacy of proposed treatments and is not sufficient justification for routine practice, insufficient attention to data concerning patient selection, insufficient attention to treatment methodology, and lack of full disclosure in some clinical trials needs to be corrected. A more systematic collection of follow-up data is needed.