A pregnant youth pastor from Alabama and her unborn daughter have been killed, and her husband critically injured in a head-on crash at the weekend.

Youth Pastor Breanna Brown Eaton, 24, and her husband, Jacob Eaton, were in what has been described as a "horrific" head-on car crash in Walker County on Saturday.

Both Breanna and Jacob were youth pastors at Lynn Church of God in Winston County.

The head pastor of the church, Chris Stokes, and his wife, Alisha, were travelling back in a different car from the Eatons when the crash took place, after the two couples and other praise team members had led worship at a women's conference in Cullman earlier on Saturday.

Pastor Chris Stokes and his wife were driving behind the Eatons when they got stuck in heavy traffic on the Alabama 69 in Walker County.

Alisha has explained that she and Breanna, who were both passengers in the cars, had been texted back and forth during the journey.

When the pastor and his wife were stuck in the gridlocked traffic, they realized there had been a bad accident up ahead on the road, and they tried to call the Eatons but could get no response.

Alisha became so worried that she ended up getting out of their car and walked up the road to the crash site, where she realized their friends had been involved in the terrible accident.

Alabama State Police have said that the Eatons' 2016 Kia Forte had been hit by a 2008 Ford Taurus. The Ford had left its lane and crashed head-on into the Eatons vehicle.

Breanna was eight months pregnant at the time of the crash, and the couple's unborn daughter, Adelaide Bryn Eaton, tragically died along with her mother.

Reports have described that Jacob Eaton is in a very critical condition, and is receiving treatment at UAB Hospital's Trauma Unit. It is believed he has two broken shins, a broken upper left arm, a broken tail bone, a pelvic injury, and a collapsed lung. Currently, Jacob is on a ventilator, and is unaware that his wife and daughter died in the tragic accident.

Pastor Stokes has said, "We lost a great one and Heaven gained a great one. But we know through all of this that God has a plan and purpose."

Authorities are continuing their investigations into the incident, and a GoFundMe fundraising page has been set-up to help Jacob Eaton with his medical costs and the funeral of his wife and unborn daughter.  To donate to the GoFundMe page please click here.