Hi,
That's the other prob.
It could be anything from gas, retained pee and poop to a prey item decomposing inside her due to incorrect temps. But most of those should have been either fairly temporary or fatal and you say she is currently doing fine.
How long did the swelling last - it looks from that pic that she is swollen all the way down to the vent which is not what happens with ovulation.
Anyone else have any good ideas on this?
dr del