The incident happened around 4:45pm in the parking lot of a grocery store in the 200 block of South Egret Bay Boulevard.
The woman was waiting for her husband to finish his shift. She had her one-year-old son sitting on her lap in the front seat of the car when another woman approached and tried to pull the baby out of her lap.
The mother was injured as she tried to fight off the suspect, who's been identified as 51-year-old Melany James. Thankfully, a bystander jumped in and put a stop to the attack.
"She was trying to roll the windows up and lock the doors and get the baby out of the way," League City Spokeswoman Kristi Wyatt said. "During the situation, the suspect actually scratched her several times in the face. A citizen who was actually in the store came out and intervened and tackled the woman and held her until police were able to get here and make an arrest."
The mother was treated for the scratches on her face, as well as others on her back, at the scene by EMS.
Meanwhile, James is behind bars, being held on a $20,000 on an attempted kidnapping charge.
Police say James and the victim did not know each other.