Data collection has commenced for Gestational Breast Cancer (GBC) in Australia and New Zealand, for all births from 1^st of January 2013. This quantitative study will continue for 2 years.

Criteria for GBC inclusion: All pregnant women with first diagnosis of breast cancer during current pregnancy, or in the 42 days (6 weeks) postpartum with:

• Pathological diagnosis of breast cancer, or
• Confirmed diagnosis of breast cancer from medical record, where pathological report is not available