Is it safe to breastfeed while taking Rogaine?

You can breast feed while taking Rogaine but if you are concerned always speak with your doctor.  The drug references says : "Probably Safe"

Check with your doctor. I take these on a case by case basis. In 2001 the American Academy of Pediatrics published a helpful guide as to the safety of medications during breastfeeding. It's important to always check with your physician before starting any medication during breastfeeding. However, topical minoxidil was felt to be safe for women who are breastfeeding.  You can see the report and link in a blog of mine from many years ago. 

Always speak with your doctor about any medications you use when breast feeding. If you were my daughter, i will tell you that some of the Rogaine will get into your system and may impact the baby, so why risk it.