Something one does not want, is to have a bad day at work, then wake up as a pony, not when said pony is sore and battered and has an odd feeling in her abdomen
Reproduction, it's a perfectly valid thing that makes total sense. When a mare and stallion love each other very much... Blah... Blah... Blah. Here's a foal. That's how it's supposed to work. Except for when it does not.
Celestia swells with life. It's a miracle, one every mother experiences at least once. It is a time for growth, physical and otherwise. It's also a time for cravings. Celestia wants a cake. They mean to prevent her from reaching it. Good luck.
Heat season was always the worst for Twilight, especially since coming to Ponyville. However, thanks to her accident with the Want It, Need It spell and her clones, she has a great outlet this season. The consequences, however, are big.
Princess Luna is having her foal. The best medical staff are at hoof to ensure a safe delivery that can be celebrated across Equestria, but there is one more surprise left.
Twilight is rather surpised when Zecora makes an unexpected visit to her door. She's even more surprised when Zecora tells her she's pregnant, with Twilight's foal.
Applejack thought, after escaping from Zecora's hut after the... incident, that she wouldn't have to worry about the events of that night ever again. However, when she finds Zecora in her house, she learns something rather... shocking.
Princess Luna is going to have a foal, and the big day isn’t far away. With little time before the young one arrives, she is coping with carrying a foal inside her as well as addressing issues that only an expectant alicorn can ever fully understand.