This comic is based on the following short story by Kassaz:
https://www.fimfiction.net/story/526921/19/short-stories-with-pregnant-ponies/time

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Twilight Sparkle paced back-and-forth in her library more slowly than she’d prefer, but the unicorn’s gravid form prevented her from having a more energetic episode. Her dictionary listed over a dozen definitions for time, and most of them were applicable! She needed more time to get the foal’s nursery ready, more time to prepare herself for motherhood, more time to begrudgingly ask for time off from her studies, and then there was that time she was dreading the most! Her beautiful checklist, which wrapped around her body many times before leaving the room in at least three different places, was only ninety percent completed for Celestia’s sake! She’d had nearly a year to prepare, and knew she’d squandered precious minutes here and there, somewhere. She thought about casting a spell on her belly to give them more time, but knew she shouldn’t.

She froze with a splash. It was time.