I thank Mayo et al for responding to my commentary1 by providing additional data. In their within-woman analysis, they report a slightly greater risk of short intervals when the child whose birth began the first interval was born preterm rather than at term and when the child was delivered vaginally rather than by cesarean. Although Mayo et al do not provide this information, I employed the STATA metan command2 to calculate that these two sets of odds ratios do not differ statistically from each other (P for heterogeneity .08 and .32, respectively), and the differences probably are not clinically significant. I await comparable data from Australia and Canada. In the meantime, I believe that my assessment1 remains valid that healthy women who have completed an uncomplicated pregnancy can be advised that decisions regarding timing of subsequent pregnancies should be based primarily on personal desires regarding child spacing and ultimate family size and only secondarily on obstetric concerns.