An American couple, who were en route to hospital, lost their unborn baby boy after a horrific car accident.

High school sweethearts Jessica (20) and Justin Mitchell (23) from Texas in the US were driving to the hospital where Jessica was due to give birth when Justin suddenly had to swerve to avoid a tree branch in the road, Mirror News reports.

The newlyweds were reportedly stuck in a ditch for an hour before help came.

Justin broke his back and pelvis, while Jessica needed an emergency C-section after suffering neck and other injuries, Daily Mail reports.

Jessica's mom, Brenda Mize, told local media that the baby boy, who was named Sebastian and weighed 4kg, didn't survive the accident.

"The baby didn't make it," Brenda said. "They needed to do a C-section to assess Jessica's injuries.

"He looked like his mom and had his daddy's nose; we did get to hold him for a little while and spend time with him."

The couple were reportedly able to spend time with their son before being taken to the intensive care unit, KLTV reports.

"It's just a really hard situation, and these kids need love and prayer," Brenda said.

A GoFundMe page has been opened to help pay for Jessica and Justin's medical bills.

Sources: Mirror, Daily Mail, KLTV