Interesting take from the end of the finale.....from EW.com's TV Recap

Spoiler: show
One cliffhanger to ponder: What did Jenner whisper in Rick’s ear? Topping the list of possibilities: "Lori's pregnant." The daddy? Most likely, Shane.

I was thinking it was more Jenner told Rick something he discovered before that room exploded in episode five....but Lori being pregnant by Shane from the woods romp is more believable.