An observational study on the course of pregnancies in women with hereditary breast cancer (BRCA mutation). Participants with hereditary breast cancer who have not been pregnant are also being sought as controls.

Breast cancer (mammary carcinoma) is a malignant disease of the breast tissue characterized by the uncontrolled proliferation of breast cells. A major cause of breast cancer, particularly at a young age (usually before age 40), is hereditary genetic changes such as the BRCA1/2 mutation. If this genetic mutation is present, the risk of developing breast cancer or ovarian cancer is significantly increased. Fortunately, successful treatment is now possible even for these patients, allowing them to become pregnant after treatment. Hormonal changes during pregnancy could potentially affect the known cancer—even if treatment has ended—for example, with regard to the risk of a relapse (recurrence).

The aim of this observational study is to investigate the effects of pregnancy on a known hereditary form of breast cancer. To this end, the course of the pregnancies and any complications experienced by the patients are being retrospectively documented. In addition, the patients’ disease progression is monitored over a ten-year period. The study examines the extent to which disease-related events might be associated with pregnancy. To this end, data will be compared between two different groups: Group 1 comprises women who had at least one pregnancy following their initial diagnosis of breast cancer, while Group 2 comprises women who did not have a pregnancy following their initial diagnosis. The study is strictly observational; participation does not involve any additional treatment.

Patients between the ages of 18 and 40 with hereditary breast cancer (BRCA gene) with or without a subsequent pregnancy are eligible to participate in this study. The initial diagnosis must have occurred between January 2000 and December 2012.