A pregnant woman was rushed to the hospital Monday, after an argument she had with her teenaged sister took a violent turn.

According to the San Francisco Police Department, a 16-year-old woman invited her 22-year-old sister to meet her on Monday morning on the 200 block of Broadway Street, which is between Battery and Sansome Streets.

When the older sister arrived at around 10:15 a.m., the two women "got into a verbal argument that turned physical," police say. The teen knocked her older sibling, who is seven months pregnant, "to the floor and began kneeing [her] in the stomach," police say.

The teen fled and has not been arrested as of this morning, police say. Her sister was transported to the hospital for treatment of stomach pains as a result of the attack, and is expected to survive.