Jamie Lynn Spears risks Maddie Briann's life for natural delivery

"The baby's heart rate dropped every time she tried to push," a family insider tells Star. "They did an ultrasound and quickly discovered that the umbilical cord was too short." But despite the doctors' dire warnings, the 17-year-old "was adamant about having a natural delivery."

Everyone in the room at Southwest Mississippi Regional Medical Center in McComb, Miss., pleaded with Jamie Lynn to listen to the doctors — including big sister Britney. Brit had already been with Jamie Lynn for hours, massaging her back as she endured painful contractions. "But she got mad," says the insider. She told Jamie Lynn to "just have a damn Caesarian," as she did. "Britney then ran out in tears because she couldn't bear to see what was happening."

The girls mother, Lynne, only added to the tension. "Lynne was already angry because her daughter didn't want her in the delivery room at all," says the source. "But she had insisted on being there, along with Casey Aldridge, Jamie Lynn's boyfriend. Jamie Lynn cussed and yelled at her mom, and told her to get out. She cursed Lynne for bringing her into the world to bear such pain."

Image WENN