The President managed to steady the pregnant lady as she started to faint half an hour into his speech.
He began to sense movement behind him, and turned to steady the woman, Karmel Allison, as she wavered on her feet.
Karmel had been smiling throughout the speech but appeared to become dizzy and unsteady as time went on. Obama stepped in just in time, and appeared just the hero as he caught her and said "I gotcha, you're okay."
The catch was met by applause from the impressed crowd and was followed by laughter when Obama quipped: "This happens when I talk too long."
Karmel Allison, who later said she felt dizzy because she is diabetic as well as pregnant, tweeted: "I'm ok world - just got a little lightheaded. Thanks, @BarackObama for catching me!"