Absolutely, plenty of well off parents will pay for it possibly...

Absolutely, plenty of well off parents will pay for it possibly with no real need. Maybe it's my personal skew but one of the reasons I really like this product is because pregnant women, globally, who can't afford or get access to hospitals or obstetricians regularly may be able to rent/borrow a monitor from a hospital or GP or even pharmacy and have peace of mind as well. Even in wealthier environments, most women would still happily rent it as it's something you only really use for maybe 6 months and probably only twice in their life. Second-hand markets in pregnancy/baby equipment are also huge, so after an initial burst of sales, I'd expect a lot of women to buy them there, or get them as hand-me-downs, which is very common too.

The revenue, in my opinion, is in the app subscription.