The biggest issue is we don't know why there is a human sacrifice to the planet. You need to be super specific about the whys and hows in a pitch without getting too world-buildy and this may prove a little difficult with your story. Since I know a little bit about your book (y'all should read her query to become familiar!), let me brain on a couple alternatives for you:

Single-mother Ren discovers she's the next offering in a centuries-old tradition of sacrifice to the planet. She becomes a fugitive to prove the sacrifices are unnecessary. If she doesn't, she'll lose her son, and her life. #mockpit #A #SF #SFY

or

After discovering she's the next sacrifice in a centuries-old planetary tradition, single-mother Ren becomes a fugitive to prove the sacrifices are worthless. If not, she'll never see her son again. #mockpit #A #SF #SFY

The idea is to present your character + plot/conflict + stakes. If you can spare the space for some voicey bits (like in the second option... There's plenty of room to do a little futzing.), then use it if you want. If you don't... I AM noticing a trend toward shorter pitches happening during pitch events.