The device tracks progesterone levels via saliva. It's currently possible to track those levels via urine or blood, but saliva is probably the most convenient.
But here's the catch. If you desire to avoid pregnancy, you avoid sexual activity during the fertile window that the device indicates. This is known as a fertility awareness method, and in Catholic circles it's also known as natural family planning.
It is not a contraceptive in the sense that it allows you to have sex during the fertile part of your cycle but not get pregnant.
30 hours is two days, two is more then one and thus multiple. Plus that's just the expectation, even in that same article a doctor said their longest shift was 72 hours. What we want and reality often diverge. We have to acknowledge reality
I don't disagree it's bad, but it's real. People do it all the time. First responders often have a 24 hour shift, throw in contingencies and it's two days.
Soldiers on mission often don't get to sleep and if your the unlucky bastard to pull sentry duty, sucks to be you. Deal with it.
There are plenty of people who routinely go multiple days without sleeping. First responders, military, students. It's doable. It's not healthy long-term. But you can do it once or twice.
Stay active, avoid situations where you get bored or become calm. Use tremendous amount of stimulants. Zyn puches work, hot sauce, chew, energy drinks, coffee, lipping coffee grounds. If you have to wait for something, and you can't stay active, do some exercise, run a little bit, jumping jacks. Anything to keep the blood flowing.
Your attention and reaction time is going to be reduced, don't drive vehicles, don't do anything that put you in danger if you fall asleep.
Recognize once you stop moving you're going to sleep for a very long time. So get to a safe space and then crash
Niche communities. Large spaces are built of small niche interest groups. The tooling around small spaces needs to be first class if we want the larger space to be healthy