The drama unfolded at about 7:30 p.m. Wednesday when multiple shots rang out as the woman was walking in the park, in the 7300 block of 45th Avenue South, with her husband and four children.
Witnesses heard the shots and saw two men firing guns at each other, said Renee Witt of the Seattle police.
The woman, carrying her infant child, was caught in the crossfire and sustained injuries from shrapnel on her arm, neck and face. The baby was not hurt.
The two suspects then fled.
The first suspect, described as a black male wearing a red shirt and black pants, got into a dark SUV and drove off. The second suspect, described as a black male in his late teens wearing dark shorts, was seen running away to the west and hiding a gun in a drainage pipe.
Officers arrived within seconds and launched an investigation. Shell casings were recovered, along with the handgun.
The 34-year-old mother sustained a shallow puncture wound from shrapnel. She was treated at the scene.