of CT, GMV and CSF for each scan were obtained by taking the first 
eigenvariate (akin to a ‘weighted mean’57) across all voxels within each 
parcel of the Schaefer 400-region atlas58. We then averaged ROIs across 
networks, which were defined by the 17-network Schaefer scheme58,59. 
Global measures of CT, GMV and CSF were computed for each session 
by summing across all voxels within the respective output image; 
total brain volume was computed by summing across all voxels within 
each session’s brain extraction mask. Our findings held when using an 
SST derived from all 26 MRIs (prepregnancy through postpartum), 
as well as when estimating the mean (versus weighted mean) of all 
voxels within each parcel. The ANTs CT pipeline is highly validated 
with good test–retest reproducibility and improved ability to predict 
variables such as age and gender from region-wise CT measurements