Mammogram, Ultrasound, MRI, and Biopsy While Breastfeeding

Breast cancer screening and detection is a critical part of maintaining good health throughout your lifetime. This is true even when you're breastfeeding. The good news is that it is completely safe to have a mammogram, ultrasound, and an MRI while breastfeeding. Also, there is very little risk with having a biopsy.

Breastfeeding causes breast tissue to become more dense (thick, fibrous), and often causes an increase in harmless lumps and bumps, like plugged ducts and milk-filled cysts. Very rarely are these lumps due to breast cancer. If you detect a lump, nodule, or bump in your breast while breastfeeding and are concerned (perhaps it does not go away after a few days or more of nursing, for example), it's always best to visit your doctor for further evaluation and exams. Either your obstetrician, midwife, or primary care doctor can help you evaluate your breast and determine if further diagnostic testing is needed.

If you are someone who receives annual screening mammograms, ultrasounds, or MRI for breast cancer detection due to your age, personal history, or family history, it's important to discuss with your primary doctor or breast specialist doctor about screening and breastfeeding. If you have a history and or higher risk of breast cancer, it is recommended to continue regular screenings.

If you are healthy and do not have a history or higher risk of breastfeeding, and you begin breastfeeding when you are at the recommended age (typically 40) for a routine yearly mammogram, most doctors advise to still go ahead with recommended screenings. Unfortunately, breast cancer can happen in people who are otherwise healthy and who do not have a family history. You may want to discuss with your doctor -- a doctor who is well versed in assessing breast cancer risk -- the timing of your screening. The earlier you are in your breastfeeding (first few months), the breast tissue is much more dense. Your doctor may suggest delaying the test for a couple of months for clearer imaging results.

The challenge with imaging screenings (ultrasound, mammogram, MRI) while breastfeeding is that because the breast tissue is so dense, the images can be more difficult to read and interpret. Because of this, it's important to request that the radiologist who reads your images is experienced in reading images of a lactating breast.

Tips for Imaging Tests While Breastfeeding

1. It's best, both for your comfort and the quality of the test, for your breasts to be as empty as possible before having an imaging test done. Plan to either bring your nursing baby or child to your appointment and nurse before the test. Or, bring a breast pump with you to use before the test. When making your appointment, let the office know that you will need time and/or space to breastfeed before the test(s) are performed.

2. Be sure when making your appointment at the imaging location that there is a radiologist available who is experienced in reading images of lactating breasts. Typically, there is more than one imaging clinic in a given area, in case you need to check elsewhere.

3. Let your imaging technician know that you are breastfeeding so that they can make any adjustments necessary to make testing more comfortable.

4. You do not need to stop breastfeeding or "pump and dump" before or after any of these imaging tests. Even MRI, which uses a contrast solution via IV, does not harm breast milk or pose a risk to babies/children. Only 0.04% of the solution reaches breast milk and only 1-2% of that is absorbed by baby, and therefore does not pose a risk.

Biopsy and Breastfeeding

If your doctor determines after imaging results that you should have a biopsy to check definitively for cancer, you should know that needle biopsy too is safe to undergo during breastfeeding. It is recommended that the smallest needle that can be used to determine diagnosis should be used. The only risk with biopsy is an extremely rare one and is called a milk fistula, which is chronic milk leakage. According the University of Massachusetts Breastmilk Lab, the risk is so rare that when it does happen, it is written up as a case report. Breastfeeding after a needle biopsy is safe and encouraged.

Some parents are mistakenly told that they must wean before an imaging test or biopsy, or pump and dump for a period of time after the testing. If you are told to do so, know that this advice is not based in best evidence. Seek a different opinion from someone who is well versed in breastfeeding.

Breast cancer screening is an important part of your overall health and it shouldn't be overlooked when you are breastfeeding. Likewise, breastfeeding shouldn't have to be discontinued if you need to be tested. Thankfully, the screening and tests most commonly used all are compatible with breastfeeding, so you can continue breastfeeding and do what is necessary to keep tabs on your health!