I have been on it for 10 years (various levels depending on my mg issues at the time) and the one side affect I really watch out for is gastro-intestional upset. I find if I have to increase my dosage, it is better to take smaller doses closer together rather than one large dose at 4 hours intervals. Also, I always try to eat something small or drink a glass of milk when I take the mestinon to try and settle my stomach.

I'm not sure of how it might affect having children, but based on the fact this is such a short-acting medication and is completely out of your system after about 4-5 hours, I'm not sure how it could affect pregnancy. I'm sure there are others on this site that can better address that issue than me.

Good luck and I hope the mestinon works for you.