Concentration of maternal microchimerism by parity. Scatterplots indicate all values included in the complete analysis. Repeated measures from some subjects are included; linear regression of ranks analysis adjusted for possible correlation between values within a subject via generalized estimating equations. For the comparison between parity of 2-4 compared with 1, also adjusting for age at draw date and time from last delivery, P = .02. Below the scatterplot, in tabular form, we have included data reflecting the distribution of maternal Mc quantities detected. For each level of parity, the underlying column indicates the number of samples evaluated, the median concentration of maternal Mc, and the concentrations at the 75th, 90th, and 100th percentiles for the data from all tests at each level of parity.