What women need to know about mammograms, COVID-19 vaccine

Women should pay attention to the timing of their COVID-19 vaccination shots and breast exams, according to new guidelines.

If it does not delay care, women should consider scheduling their mammogram either before receiving the first dose of a COVID-19 vaccine, or four to six weeks following the second dose of a vaccine, according to guidance released Thursday by the nonprofit organization, Society of Breast Imaging.

The new guidelines were issued after reports of both the Pfizer and Moderna vaccines causing swollen lymph nodes in the armpit area where the shot was administered.

That area of the body is also where enlarged lymph nodes can be a sign of breast cancer, according to Dr. Jennifer Ashton, ABC News chief medical correspondent.

"What they're seeing in real time is enlarged lymph nodes in women who have had the COVID-19 vaccine and they don't want that to produce confusion with results of their mammogram," Ashton, a board-certified OBGYN, said of the SBI's new guidelines. "But the most important thing is to realize that just seeing an enlarged lymph node in an armpit without a breast finding is not necessarily a sign of breast cancer."

Swollen lymph nodes after the second dose of a COVID-19 vaccine is not a cause for concern, according to Ashton.

"This is just your immune system doing its thing," she said. "This is your body doing its job."

Ashton advised people to talk to their doctor and radiologist and also make sure they know in which arm you were vaccinated.

Women age 45 to 54 should get mammograms every year, according to the American Cancer Society.

Women ages 40 to 44 should "have the choice" to start annual breast cancer screening with mammograms if they wish. Women 55 and older may switch to mammograms every two years or continue yearly screening, according to ACS.