Hopefully around 3 stone! Lol! Shame I know thats not true! I do know of someone whose placenta weighed roughly the same as her baby at 9lbs though so she probably lost around 20lbs instantly.
this is how it was broken down in my one pregnancy book
Baby: 7-8 1/2 pounds
Placenta: 1- 1/2 pounds
Uterus: 2 pounds
Amniotic fluid: 2 pounds
Breasts: 1 pound
Blood volume: 2 1/2 pounds
Fat: 5-8 pounds
Tissue fluid: 6 pounds
Total : 27- 31 1/2 pounds
With my first I had to have a diuretic for my blood pressure so by the time I left the hospital I had lost 38 lbs, with my second I lost 15 lbs, and with my last one I lost 12 lbs.
My pregnancy has been pretty normal and i've gained a lot! Baby weight for me is probably only 15 to 20 pounds.
My first I gained 40lbs. I swear within the first 3 days I had lost 25 of them!!