I had problems with my leg joints in high school and I was on antibiotics nearly constantly. One of them was Cipro. A couple of years ago, when my daughter was four months old and exclusively nursing, the docs wanted me to take Cipro. I consulted La Leche League's Medical Board and was advised to opt for an alternative if possible because a small amount of Cipro would leak into the breastmilk. Because my daughter's joints were still developing they thought this would be detrimental. I had no problems with my docs finding a better alternative. My joints are finally stronger again. Still weaker than most people's. But, I haven't taken Cipro but just a few times in the last 6 years.