text: 50 
  Weeks since conception 
  
  colors denote pregnancy stage. The participant underwent IVF to achieve 
  pregnancy, allowing for precise mapping of ovulation, conception and gestation 
  week.**d**, Summary (that is, total) of brain measures throughout the experiment. 
  Generalized additive models revealed GMV, CT and total brain volume decreased 
  throughout pregnancy (see Methods for validation with cubic regression), with 
  a slight recovery postpartum. Global QA, lateral ventricle and CSF volumes 
  displayed nonlinear increases across gestation, with a notable rise in the second 
  and third trimesters before dropping sharply postpartum. Shaded regions 
  represent 95% confidence bands; solid lines indicate model fit; dashed line 
  indicates parturition.  **Fig. 1 | Precision imaging reveals neuroanatomical changes throughout**
  **gestation. a**, Standard medical demarcations for pregnancy stages (that is, 
  trimesters) by gestation week (the image is created with BioRender.com). 
  **b**, Steroid hormones increased significantly throughout pregnancy and dropped 
  precipitously postpartum, as is characteristic of the prenatal and postnatal 
  periods.**c**, A healthy 38-year-old primiparous woman underwent 26 scanning 
  sessions from 3 weeks preconception through 2 years postpartum. Scans were 
  distributed throughout preconception (four scans), first trimester (four scans), 
  second trimester (six scans), third trimester (five scans) and postpartum 
  (seven scans); tick marks indicate when major measures were collected and 