In short, she reacts badly to hormonal treatments, is "too young" to get her tubes tied*, and is not dating someone who has had a vasectomy (she's currently single), so she cannot meet the "primary birth control" criteria. Please note that she has a PhD in psychology specializing in sex and gender topics, so she is not uneducated about birth control, its effectiveness, and how to use it. But because she doesn't meet criteria as listed on a website, she cannot get this medication in the United States.
What makes this law so much more ridiculous is that if someone pledges that they have and will continue to abstain from sexual relations (taken as truth from word of mouth), they are considered fine for taking the medication. No, really. And notice the part about the boyfriend with the vasectomy? Yes, that's good, but... women are known to cheat too. So why is it that if someone says, "I do not want to have children, and I have effectively been using condoms and the morning after pill as birth control for the past decade," they are not to be believed, but everyone else's word is taken as truth?
And really, why not just say, "OK, look, if you want to take this drug, you have to get bloodwork done once a month." I know that's what I had to do while on lithium, why is this any different? I mean really, if you're that worried about the medical effects, then MEDICALLY figure it out.
In other words, this really is just a big, "Fuck you, fuck you very much," to the government for enacting such stupid laws.
* Please note that women who have had less than 2 children and are under the age of 35 cannot opt for having their tubes tied and still have insurance pay for it. Considering that the expense of this surgery is so daunting, this effectively means that most women who do not want children just cannot get it done until the age of 35.