The U.S. Food and Drug Administration said on Thursday all mammography facilities in the country will be required to notify patients about the density of their breast tissues, as that can potentially make detection of tumors more difficult.

Breast density can influence the accuracy of mammography, which relies on X-rays passing through breast tissues to diagnose and locate tumors.

Mammograms remain the best tool for screening and detection of breast cancer, which is the second most common form of cancer among women in the United States, according to the Centers for Disease Control and Prevention.

The agency recommends patients with dense breasts, a normal and common finding in mammograms, to discuss their individual situation with their respective healthcare providers.

The updated rules will help ensure patients receive information on the potential need for further evaluation or a repeat mammogram, the health regulator said.

"Increasing early detection is the best way to improve outcomes, and this new standard does just that," Congressman Brian Fitzpatrick said in a statement.