There has been little research conducted on critically ill pregnant and postnatal women. When developing a research protocol to conduct a prospective multi-centre survey on this study population, we found there were vital concerns that needed addressing prior to the research proceeding. Prompt identification of the study population and valid, reliable data collection were two aspects that needed particular attention with study recruitment potentially occurring in a total of eleven clinical areas from seven hospitals. In this paper we outline the particular issues faced by us when conducting multi-centre research on a study population that occurs infrequently and unpredictably, and when there is a necessary urgency to identify eligible study participants. The key strategy to overcome these difficulties, was the creation of 'Core Research Teams' in each clinical area. Our experience of using Core Research Teams in our pilot study is described in this paper. We found that the Core Research Team model is a very positive strategy to overcome the methodological challenges when operating a multi-centre study.