“At three o’clock the following morning, on April 22, 1923, Edna gave birth to a baby girl. They named the child Betty Mae Page according to her birth certificate, but when she became old enough to write, the spelling changed to Bettie.”
Notes on the birth name of pinup model Bettie Page, from Richard Foster’s 2005 book The Real Bettie Page. (Still available at Amazon.com.)
Commenter Mike Duffy asked about the correct spelling on our previous post about Page, where the video clip title card identifies her as Betty Page. She seems to have answered to both spellings, though “Bettie” was the preferred.