Pregnant cats belly has "dropped"

My Sugar Babies, belly had "dropped" today. It is really noticable. Just curious is this a sign of pre labor? She is still eating and isnt nesting much since two days ago. She is sleeping alot as usual.
Could anyone help, let me know if this is a sign and how long usually after the belly drops does it take before full labor?
Thanks so much for all your help.
Sue

my cats belly dropped two days before she gave birth. my vet told me its the babies moving into the birth canal.

Today I noticed a small drop of blood from her vulva area. Is this normal or should I be concerened. Like I said yesterday her belly has dropped and lastnight she actually went into the nesting box for a few seconds ans scratched like crazy and jumped back out. TOday she is just laying on the floor next to me all day sleeping. But I noticed her cleaning herslef and seen a small drop of blood and it worried me.
Sue

I removed your one thread because it was a duplicate. I am no expert on pregnant cats, more on orphaned kittens is my specialty, but I seem to recall small drops of blood are normal for a pregnant female. If you look at that one website above that I linked to perhaps you will find reassurance there?