What do you think about data privacy when building or using health apps?

Before building the app I ran a small survey with 53 mothers. Almost all of them, 96 percent, had used a pregnancy or health app that had a documented privacy violation at some point. That number stuck with me because it looks like It is not a niche problem.

So I am curious how other founders and builders here think about this. Do you treat privacy as a feature you add later, or as something that shapes the architecture from day one? And for anyone who has used health apps as a user, has a privacy issue ever changed which app you trust or which one you deleted?

Just want to hear how other people in this space think about it.