Hi Marierose

This is definitely a question you could ask of your doctor but in the meantime let me see what the literature says.

Here is the the official Plan B site  and here is their phone number to call to ask questions:  1-800-330-1271

Here is what they say about how often you can take it but bear in mind that they are the folk manufacturing this pill:  "Plan B^® should only be used in emergencies, but there is no medical reason why you can't use it more than once. Don't be afraid to use Plan B^® when you need to, but remember that it should never replace routine methods of contraception as it simply isn't as effective."

And here is an article which says: 

"Single-use of Plan B is up to 89 percent effective at preventing pregnancy, with a more than 10 percent chance of pregnancy during each cycle of use. Over the course of a year, a sexually active woman who only uses Plan B for pregnancy prevention would have a pregnancy rate equal to that of a woman using no contraceptive."

So it seems one of the biggest dangers of repeat use is that it loses its effectiveness.

I would ask your doctor about this to be certain that there are no other risks. 

Thank you for your question.