This is based on personal experience.  When my 2nd Child was 3 months old I
had to have a complete Hysterectomy.  My Gyn stated that I would be able to
continue Breastfeeding.  I was put on an antibiotic and Premarin.  I was told
that I had to pump and dump while on the antibiotic (Wish I had been on
Lactnet then) but after the antibiotics were out of my system that I would be
allowed to continue BF.  I Breastfed for almost a year on Premarin and it
didn't seem to have any effect on the quantity of breast milk.  Hope this
helps.

Brenda Noyes
Breastfeeding Peer Counselor