Board Thread:General Discussion/@comment-3456168-20151013014353/@comment-25926288-20151013014742

I'd say inbetween 12-15 weeks.

She got pregnant sometime during the 6 weeks, then 3 weeks passed until Heart of Gold, then maybe another week until Emma disappeared, then another 6 weeks forgotten.

So, that is a maximum of 16 weeks. But I wager around 12-15. When will she show? Well, whenever the writers and staff realize she'd far enough (They don't seem to be good with math).