propranonal (inderal)

I have been on propranonal for almost 20 years now for migraine headaches. I am going to be 30 in a couple of days. Hubby and I have been trying to conceive with no luck. The fertility doc told me that he wants me to get off of the propranonal as it causes small birth weight. This drug has really helped me in regards to lessening my migraines. I am just wondering if anyone else has been on this for a long time and then gotten off of it with success? Any help is appreciated.