Eight causes of nipple pain How deep is a vagina? In some states, women whose mammograms show heterogenously dense or extremely dense breasts must be told that they have dense breasts in the summary of the mammogram report that is sent to patients sometimes called the lay summary. This due to the ability of MRIs to miss some cancers that would have been detected with conventional mammography, as a result, MRI screening for breast cancer is most affective as a combination with other tests and for certain breast cancer patients. Pregnancy causes elevated levels of the hormone prolactin , which has a key role in the production of milk. To determine the laws in your state, contact your state representatives or public health department and visit AreYouDenseAdvocacy.