Hi, I just wanted to set the record straight on how Depo works: it puts the ovaries in a resting state so that they don't release any eggs, therefore they can't be fertilized. This is why so many women don't have periods when they get this shot. Regarding mood swings, it's worked great for me because it actually leveled out my mood swings somewhat; apparently I have a hormone imbalance and it helps me, but I can see where it would be different for others. I've been getting the shot for about 10 years now, and I've been extremely happy with it. My husband and I don't plan to have any more children, so I'll probably be on this til I hit menopause!!