The U.S. Preventative Services Task Force says women should start getting mammograms at age 40.

The new guidance says those at average risk in their 40s should get a mammogram every other year. Previously, their advice was to start getting mammograms at age 50.

Northwell Health Chief of Breast Imaging Dr. Nina Vincoff says the previous advice did not go with what has been proven to save lives.

"Their guidelines have never been completely in sync with all the other guidelines that are out there," Vincoff says. "So, the American College of Radiology, which is the governing body for radiology has said for a long time that they recommend annual mammography, for average risk women, starting at 40."

Some insurance companies use the task force's recommendations to determine what they will and won't pay for, which could put some women in a dangerous position.

Vincoff disagrees with the recommendation that women in their 40s should only be getting mammograms every other year.

"If you wait every other year to have a screening, you're taking a chance that your breast cancer - if you have one - is going to be larger by the time it's found," Vincoff says. "And even if you don't die of breast cancer, you're going to require more aggressive treatment."

She says breast cancer screening is a conversation that should start in a woman's 20s, with decisions based on individual risk. Higher risk women could need earlier screenings, require ultrasound or MRA and could need to be screened more frequently.

"They need to talk to their doctor about their personal medical history and about their family medical history to determine whether they really at average risk because it turns out that they're at higher risk then these guidelines don't apply to them at all," Vincoff says.

New York state law entitles women with private insurance to annual mammograms starting at age 40. Medicaid and Medicare also cover one annual screening at that age.