Can I get a tattoo over birthmarks?

It's not that I feel insecure about them or hate them but my birthmarks on my back might get in the way of getting a back tatto I've wanted for over 6 year. Some birthmarks are slightly raised (only if you touch can you notice it) and the tattoo I want stretches across most of my back. Is it possible? I've got about 4-5 birthmarks the size of peas spread out near my left shoulder blade all of which are brown