KNBC-TV captured the scene on video, including one clip that showed the woman sitting on a bus bench with the street in front of her closed.
KNBC interviewed a
"The first thing we'll try to do is get in an ambulance," he said.
Some in the crowd took to social media to show pictures and video of the unidentified woman while she sat on the bench, waiting to get to the hospital.
Medical staff from the hospital came to help the pregnant woman, witnesses said.
"A few people in scrubs are there now. Still no baby. Still no #Obama," Clifford tweeted with a picture.
The story was also reported by the Blaze website.