If they left you an ovary, TOM still applies.

What did you eat the day before your weighin?
You could be retaining water or it could be the weight of what you ate. A pound of food remains a pound whether it is inside you or outside of you. And if you didn't have a______, it will show up on the scale. (sorry to be so vulgar, but I think this is need-to-know information).

Good Luck and keep on truckin'