Can one get an accurate mammogram while breastfeeding?

Best to Wait: The breast tissue is extremely dense when breastfeeding, making it almost impossible to interpret a mammogram. If one has a lump, it is far better to have an ultrasound +/-needle biopsy (if absolutely necessary) rather than a mammogram.

Breastfeeding: The lactational changes of the breast make it more "dense" and may limit the sensitivity for detecting cancer, so in the screening setting best to wait a few months following cessation of breastfeeding. If you have a lump or other symptom, ultrasound would be first imaging study of choice.