text: Diffusion imaging: 
  DSI Studio’s correlational tractography (Yeh et al., 2016) was used to analyze the relationship between white matter 
  structure and gestational week (n = 16). A truncated model was run to examine the relationship between white matter and 
  sex steroid hormones (n = 14) for the subset of diffusion scans with paired endocrine data during gestation. A non-parametric 
  Spearman correlation was used to derive the correlation between gestational week and endocrine factors and our metrics of 
  interest (QA and MD; see Table S9 and Fig. S10 for MD results) because the data were not normally distributed. Statistical 
  inference was reached using connectometry, a permutation-based approach that tests the strength of coherent associations 
  found between the local connectome and our variables of interest. It provides higher reliability and replicability by correcting 
  for multiple comparisons. This technique provides a high-resolution characterization of local axonal orientation. The 
  correlational tractography was run with the following parameters: T-score threshold of 2.5, 4 pruning iterations, and a length 
  threshold of 25 voxel distance. To estimate the false discovery rate (FDR), a total of 4000 randomized permutations were 
  applied to obtain the null distribution of the track length. Reported regions were selected based on FDR cutoff (FDR < 0.2, 
  suggested by DSI Studio), and contained at least 10 tracts. For visualization of global and tract QA at each gestational stage, 
  mean QA values were extracted using DSI Studio’s whole brain fiber tracking algorithm and ROI-based tracking using the 
  default HCP842 atlas (Yeh et al., 2013). 