The six mothers from Belgium, who were all between 32 and 39 weeks pregnant, sat opposite a canvas and waited for their babies to kick.
They were filmed for the Unborn Artists charity campaign, which was set up to raise awareness of how many unborn babies in Africa won't survive birth because their mothers don't have access to proper medical care.
The images have been sold at auctions and baby showers to raise money. A video of the creative process was posted on YouTube.
The video shows how, paintbrushes were initially dipped into brightly-coloured paint and then attached to the mothers' bellies using fabric and tape.
The mothers then sit upright in a chair, with a blank white canvas in front of them. The brushes hover just over the canvas.
When the babies kick, the mums-to-be are captured smiling at what's happening. Others gently patted their belly to encourage their baby to kick.