[quote=@Burning Kitty]
<Snipped quote by Double>

[s]Then I have no clue why she would it hide from Kaitou.[/s] What if she slept with someone else and has no clue who the baby daddy is?
[/quote]

You could just go with the one night stand idea. Maybe they planned to give themselves space and time to decide what they actually wanted to do... and then she died?