By Dr. Liji Thomas, MD Reviewed by Lauren Hardaker Feb 3 2026 By seamlessly tracking brain growth from the womb into early life, researchers uncover when key brain regions surge and how subtle sex differences emerge before birth. Study: Mapping brain growth and sex differences across prenatal to postnatal development . Image credit: Mapping brain growth and sex differences across prenatal to postnatal development/Shutterstock.com The perinatal period is a key window of fetal neurodevelopment,