Pretty straight forwards. Pick any mare, anywhere along the line of pregnancy from initial insemination all the way to birth, and draw it up!
You have 30 minutes to draw and 15 to submit. Have fun!
Artists:
https://www.furaffinity.net/user/mj444/
https://derpibooru.org/tags/artist-colon-snspony
https://www.deviantart.com/sonork91
https://www.deviantart.com/pimpartist101
https://www.deviantart.com/bunnywhiskerz
P.S., It’s unsurprisingly difficult to find sfw pregnancy images on derpibooru, and I get the feeling most of you won’t be adding to the already tiny list of them. ;P