text: **MRI acquisition.**MRI scanning sessions at the University of Califor- 
  nia, Santa Barbara and Irvine were conducted on 3T Prisma scanners 
  equipped with 64-channel phased-array head/neck coil (of which 50 
  coils are used for axial brain imaging). High-resolution anatomical scans 
  were acquired using a T1-weighted (T1w) magnetization prepared rapid 
  gradient echo (MPRAGE) sequence (repetition time (TR) = 2,500 ms, 
  time to echo (TE) = 2.31 ms, inversion time (TI) = 934 ms, flip angle = 7°, 
  0.8 mm thickness) followed by a gradient echo field map (TR = 758 ms, 
  TE1 = 4.92 ms, TE2 = 7.38 ms, flip angle = 60°). A T2-weighted (T2w) 
  turbo spin echo scan was also acquired with an oblique coronal orienta- 
  tion positioned orthogonally to the main axis of the hippocampus (TR/ 
  TE = 9,860/50 ms, flip angle = 122°, 0.4 × 0.4 mm2 in-plane resolution, 
  2-mm slice thickness, 38 interleaved slices with no gap, total acquisi- 
  tion time = 5 min and 42 sec). The Diffusion Spectrum Imaging (DSI) 
  protocol sampled the entire brain with the following parameters: 
  single phase, TR = 4,300 ms, echo time = 100.2 ms, 139 directions, 
  *b*-max = 4,990, FoV = 259 × 259 mm, 78 slices, 1.7986 × 1.7986 × 1.8 mm 
  voxel resolution. These images were linearly registered to the 
  whole-brain T1w MPRAGE image. A custom foam headcase was used 
  to provide extra padding around the head and neck, as well as to mini- 
  mize head motion. Additionally, a custom-built sound-absorbing foam 
  girdle was placed around the participant’s waist to attenuate sound 
  near the fetus during second-trimester and third-trimester scanning. 