When women go into labor, this sac breaks and the liquid drains out. This is more commonly known as the waters breaking.
Miss Scurry was en route to the hospital, when she realized she had just given birth after she pulled her pants down and felt her baby's head.
The baby was originally still, sparking panic. But he eventually "rubbed his face" using Miss Scurry's thumb and "pulled his little hands up".
Miss Scurry said this reassured her that he was healthy.
Miss Scurry, a mother-of-two was being driven to hospital by her fiance Ean on August 5 after she started to have intense contractions. She was 29 weeks pregnant at the time.
She initially dismissed them as just contractions, which tend to occur around the middle part of pregnancy.
Writing on her Instagram page, she said: "The contractions continued to get closer together and more intense and before I knew it I knew it was time to push.
"I called 911 because I was so scared. They couldn't understand me between the screams with contractions. So I handed the phone to my fiancé.
"I pulled my pants off and reached down, sure enough his head was right there. I pushed one time and my miracle baby was here."
Miss Scurry added: "When I looked down I realized he was still completely wrapped in the amniotic sac."
The couple believed they would make it to hospital quicker than an ambulance would reach them, so continued to drive.
The baby was originally still, sparking panic. But he eventually "rubbed his face" using Miss Scurry's thumb and "pulled his little hands up".
Miss Scurry said this reassured them both that he was healthy.
The journey to the hospital took seven minutes. They were greeted by staff running to their car.
Medics opened the amniotic sac Ean Jamal, who weighed 3lbs 1oz, was in.
Miss Scurry added: "He's doing wonderful all things considered. I know he's going to be an awesome little man! He is truly a miracle baby. We are so blessed to be his parents."
