The 22-year-old star makes the frank admissions in "letter of truth" published on her official website, warning fans that her body is changing and that they won't be seeing much of her for a while.
She wrote, "Being married is great and I can't wait to start my family.
"There's so much change going on in the world right now... not only with me, but with the world as well.
"I am going to take some time off to enjoy life.
Spears also used the letter to have a cheeky dig at her pop rivals.
"My prerogative right now is just to chill and let all of the other overexposed blondes on the cover of US WEEKLY be your entertainment... good luck girls!"
Spear's record label JIVE are far from pleased with her recent decision - having just poured millions into promoting her GREATEST HITS album.17/10/2004 14:14
With clips from more than 200 teen movies made in the decade after 1995's Clueless,...
The cameo-driven, "Mission: Impossible 2"-spoofing, movie-within-a-movie, pre-title sequence of "Austin Powers in Goldmember" is the...