title: A study of time trends in maternal-fetal x-ray exposure.
mesh_terms: D002140:California; D005260:Female; D006801:Humans; D008423:Maternal Age; D010387:Pelvimetry / Q000706:statistics & numerical data; D011247:Pregnancy; D011859:Radiography / Q000706:statistics & numerical data*; D011860:Radiography, Abdominal; D014965:X-Rays