Lynne Spears' book was a parenting book with faith elements to it

Lynne Spears had been due to release Pop Culture Mom: A Real Story of Fame and Family in a Tabloid World in April next year.

Lindsey Nobles from Christian book publisher Thomas Nelson said: "We have postponed the book indefinitely."

"Lynne needs to spend time with her family now," she added.

Pop Culture Mom had been described as "a parenting book that's going to have faith elements to it".

Shocked and scared

Jamie Lynn, who plays a schoolgirl in US TV comedy Zoey 101, told OK! magazine that news of her pregnancy was a shock.

The actress added she planned to keep the baby and raise it Louisiana for "a normal life".

Her mother added: "I didn't believe it because Jamie Lynn's always been so conscientious. She's never late for her curfew. I was in shock. I mean, this is my 16-year-old baby."

US cable TV channel Nickelodeon, which airs Zoey 101, said in a statement: "We respect Jamie Lynn's decision to take responsibility in this sensitive and personal situation.

Jamie Lynn Spears made her announcement in a US magazine

"We know this is a very difficult time for her and her family, and our primary concern right now is for Jamie Lynn's well-being."

Meanwhile Britney, who recently lost custody of her two children to her former husband Kevin Federline was asked by paparazzi to comment on her sister's pregnancy.

"My sister's not pregnant," she said.

The singer has been sent for parenting training and random drug and alcohol testing as part of her custody battle.