What Happens in Rio… - Chapter 23

I’m so confused…how did they know she was pregnant? It wasn’t the male teacher becsuse they both just came in or is thing later in the day (and he actually told everyone?)…plus isn’t she worried that people think they have been together for 3 years…while she was “engaged” to the other dude? Wont she then become the one who was actually cheating??

This doesn’t make sense…