Most often, no. It's important to treat your postpartum depression, for both your sake and your baby, but the good news is that many of the antidepressants used today are compatible with breastfeeding. You'll want to look for those that have been approved for use in breastfeeding mothers by the American Academy of Pediatrics (AAP.org). Know that weaning can often worsen depression, and your milk is providing the best possible nutrition and protection for your baby so it's actually important not to stop breastfeeding. You can find up-to-date information about various medications and their safety with breastfeeding in Medications in Mothers' Milk by Dr. Thomas W. Hale, PhD. Your local lactation consultant (IBCLC) will likely have a copy of this reference and may be able to provide the information for you. While depression can be difficult and frustrating to deal with in the early days of motherhood, treating it promptly can make all the difference.