YORK, Pa. (WHTM) — If you just got the COVID-19 vaccine you may want to reschedule your mammogram. Doctors have found the vaccine can impact your results.

“It was a dilemma in the beginning,” Dr. Kimberlee Mudge said.

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Dr. Mudge is a breast surgeon at Leader Surgical Associates UPMC in York. She experienced firsthand how the COVID-19 vaccine was impacting mammograms.

“I would say a good 4 weeks or so we were seeing patients newly diagnosed with cancer who had just had their vaccine. It hadn’t come out that this could be a problem related to the vaccine. It was very challenging, so many of those scenarios early on resulted in biopsies that perhaps didn’t need to happen,” Dr. Mudge said.

According to Dr. Mudge, when you get the COVID-19 vaccine it can cause the lymph nodes in your armpit to swell, which is a normal reaction. This is where the overlap happens. Swollen lymph nodes can also be a sign of cancer, so if you get your mammogram soon after you get the vaccine it could impact your results.

“When you get that mammogram and it’s showing enlarged lymph nodes it then triggers oh my goodness is that a reactive node. It is an interval change from your preceding mammogram do we need to do a biopsy or not,” Dr. Mudge said.

Now that doctors are aware of this overlap they have made some changes.

“We try to encourage people to delay getting their mammogram for a good 4- 6 weeks after the vaccine to help prevent that,” Dr. Mudge said.

Doctors say this does not mean women shouldn’t get a COVID vaccine or skip their mammograms, just that they need to communicate with their doctors to make sure the timing is right.