If she is pregnant, when you meet her, it should say (Rinny greets you "Hey ..., look how big my tummy's gotten! We've gotta do it while I'm like this"), Click (Non-pregnant sex acts)
scroll down until you see the option (Ask for '???')
I will not say what it is because it is a spoiler and takes the fun out of it.
Hope this helps!
Also, I'm sorry I think I may have confused you with the first post It has been a wile since I talked to rinny and I was going from memory, but I just talked to her to help with this post