Pregnancy and Multiple Sclerosis-Reply

In reply  The term prospective as used in our article¹ was very clearly defined. While the terminology was not exactly as defined by Friedman,² it was used to differentiate our case ascertainment from those of published retrospective series and from that of Birk et al.³ As our definition was in no way ambiguous, we cannot understand Rudick's long dissertation on this.We agree that power calculations are important. However, for the present study, the objective was to describe the experience in our clinic. We were thus limited by the number of patients and matched control subjects available during the study period 1982 through 1986 inclusive. We clearly explained why 1986 had to be the cutoff. Sample size is a problem for any "prospective" study on pregnancy and MS, especially if clinical information should be standardized, as pointed out by Rudick. Our study included 47 women who had