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Finding a lump in your breast is scary! Fortunately, most lumps in a lactating mother’s breasts are either milk-filled glands or an inflammation, such as a blocked duct or mastitis. If the lump is tender, it is probably mastitis. Check out this page for information on treating mastitis.


If the lump does not go away after a week of careful treatment for a blocked duct/ mastitis or if you are experiencing sudden flu-like symptoms or a high fever, or are at all concerned, contact your healthcare provider. If you notice red streaks on your breasts seek medical attention as they are a sign of infection that, left untreated, can develop into sepsis, a life threatening complication of an infection.



Although breast cancers in lactating women are extremely rare they are known to occur.1 Changes or abnormalities of any kind in your breast should be investigated with the same level of concern regardless of whether you are breastfeeding or not. Research shows that breastfeeding is associated with reduced mortality in women with breast cancer.2


If you need a mammogram while you are breastfeeding, it can usually be performed on your lactating breasts.However it is not necessarily recommended for high risk (BRCA) women under 303 : your healthcare professional will be able talk through your options with you.


Contrary to advice sometimes given it is possible to read a mammogram of a lactating breast (breasts that produce milk are called lactating breasts). Due to milk production, there is more dense tissue present in a lactating breast than in a non-lactating one:  this may make it harder to read the results. The amount of tissue in your breast depends on the frequency that your baby is breastfeeding, depending on the age and stage your baby is at you may not be able to do adjust the frequency of feeds. To help reduce the amount of milk prior to a mammogram, you could bring your baby and breastfeed immediately prior to the procedure.


Ask for a radiologist who has experience reading mammograms of breastfeeding women.

X-rays do not affect human milk4, so you can safely resume nursing immediately after the mammogram.


If the lump you’ve discovered needs closer examination, you can feed immediately after fine-needle aspiration as well as after a biopsy or other surgery. It is important to let your doctor and/or surgeon know that you are breastfeeding so they can select appropriate medications for you.


If you have a biopsy or surgery you may need to adjust breastfeeding positions for a time to avoid putting pressure on the sore spot, or to express milk while you heal. Your local LLL Leader can help with suggestions – find local support here.



1 (Unar- Munguia, Breastfeeding Mode and Risk of Breast Cancer: A Dose–Response Meta-Analysis,Journal of Human Lactation, Vol 33, Issue 2, 2017;

Ying Zhou et al, Association Between Breastfeeding and Breast Cancer Risk: Evidence from a Meta-analysis, Breastfeeding Medicine. Apr 2015: 175-182

2 Lööf-Johanson Margaretha et al, Breastfeeding Associated with Reduced Mortality in Women with Breast Cancer, Breastfeeding Medicine, July 2016, 11(6): 321-327.

3 Carmichael, H., Matsen, C., Freer, P. et al. Breast Cancer Res Treat (2017) 162: 225.

4 Philip O. Anderson, New and Unusual LactMed Topics, Breastfeeding Medicine. Nov 2016, 11(9): 430-432

*Parts of the contents of this page was generously supplied by La Leche League International

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