Friends of Britney Spears fear the pop star may be pregnant after she skipped a July appointment for the Depo-Provera shot.

“She missed a shot in July,” says a friend of the singer, “and she was late getting another shot,” Spears friends tell Life & Style Magazine.

After complaining that the birth control injection made her gain weight, Britneyquit Depo-Provera and switched to traditional birth-control pills.

“But she’s constantly forgetting where she put them and to take them,” says the insider. “She seems to find it amusing — she laughs at how scattered she is.”

L&S moles also report Britney slept with friend Sam Lutfi, and other friends believe she and producer JR Rotem have been “hooking up.”

“When her friends ask if she’s being safe, Britney says it’s just casual sex. She seems to think that just because she isn’t in a formal relationship, she’s somehow immune to getting pregnant.”