White spots or stains on my teeth?!

White spots or stains on my teeth?

I've had white spots on just my front two teeth since I was a teenager and I've never been able to get rid of them. I brush twice a day with a good toothpaste and I've never lived anywhere there was heavy flouride in the water. It has come and gone over the years. It varies from almost negligible to looking like someone colored my teeth with whiteout. I've recently stopped drinking soda and the spots have faded to the point where I can smile without being self conscious. I asked my dentist and she thinks that maybe it was caused by mother taking antibiotics while she was pregnant with me (which she did). It still didn't answer my question as to what it was or what I could do about it.
I've tried whitening rinses like Listerine and Hydrogen Peroxide, but it didn't seem to do much.
I'm okay with giving up soda, but it is starting to wear on me. I miss it!!
Any suggestions as to it's cause and what can be done.

2 months ago
Sorry, I wasn't very clear as to why I quit drinking soda. I thought that maybe my diet was affecting the spots so I changed things. I stopped eating processed sugar and that made no difference. I then decided to cut out soda and that made the spots fade. So, it's been three weeks now and they haven't come back. I don't know what that means, maybe there is a component in soda that makes the spots worse.
Any thoughts?

i have white spots too on my teeth and i was told it was a calcium deficiency. i have heard it can be caused from the antibiotics at birth too. my dentist told me to use the teeth whitening strips so i tried them. they didnt completely eliminate the spots but they made them alot less noticable. maybe that would help =)