Yeah correct, birth controll could be another possibility, but not for a reason yall thought.
From all the data we got about her, she is not that kind of girl, she don't sleep with anybody and do sex freely. She for a moment willing to get her boyfriend to join her exc live, not confirmed it will be her boyfriend but that's the most likely candidate, but to this date the live never happends.
Then for what reason she might drink it ? She probably want to play it save and also currious. She had tendencies to buy and use weird product. From tits cream and pills. So she getting the idea of birth controll is likely too.
But that considered , source of hormon could be from anywhere not birth controll only. Afterall from a couple of old live it's confirmed that she drinks some tits enlargement pills.
She is not that type of girls, but she loves to buy and drinks weird things she found online, and she really love eating food with really high callorie. Birth controll is a possibility but other source of hormon is more likely