Your breasts undergo amazing changes when you become pregnant. As they develop milk ducts for breast feeding, they often double in size and become heavy with extra fluid. The breast tissue also feels more firm and "lumpy bumpy." These changes can make it difficult to diagnose breast cancer. Concern about how an imaging technique affects a developing baby also may limit some of the diagnostic options for women with a suspected breast cancer.
Several small studies have looked at how breast cancer is most often first detected during pregnancy, and the safety and reliability of mammography, ultrasound, and other breast cancer imaging techniques during pregnancy.
Signs of breast cancer during pregnancy
Most breast cancers diagnosed during or shortly after pregnancy first appear as a painless breast lump. Still, most lumps found during pregnancy aren't cancer.
It's reassuring to know that if you develop a breast lump during pregnancy, it is unlikely to be breast cancer. But you should still bring any suspicious lump to the attention of your doctor and go through the proper tests to find out whether it might be cancer. DO NOT WAIT UNTIL YOU DELIVER OR STOP BREAST FEEDING TO GET THE LUMP CHECKED OUT.
So, if you're pregnant and you have a breast lump that needs checking, which tests are safe for you and your baby?
Mammograms during pregnancy may be considered for women with signs or symptoms of a possible breast problem.
Small studies have found that it's fairly safe to have a mammogram when you're pregnant. Only a small amount of radiation is needed for a mammogram and the radiation is focused on the breast, so most of it doesn't reach other parts of the body. For extra protection, a lead shield is placed on the belly to block any possible radiation scatter.
Regular screening mammography in women without any symptoms is not done during pregnancy.
Ultrasound is considered a safe tool for "seeing" inside the breasts of pregnant women. It is usually used before mammography to evaluate a palpable lump (a lump you can feel).
In both pregnant and non-pregnant women, ultrasound can accurately tell if a lump is a harmless cyst filled with fluid, or a solid mass that could be cancerous. But it is much less accurate at distinguishing between a solid lump that is breast cancer and a solid lump that is not.
According to the U.S. Food and Drug Administration, the safety of magnetic resonance imaging (MRI) during pregnancy hasn't been established. Still, most small studies looking at MRI during pregnancy show it causes no problems. MRI is sometimes used to check breast lumps in pregnant women that look like they might be cancerous on a mammogram. Talk to your doctor about whether this type of test is safe for you and your baby.
To diagnose breast cancer with certainty, in both pregnant and non-pregnant women, doctors need to remove a small portion of the suspicious breast lump. This procedure is called a biopsy. Such tissue can be removed by a needle (needle or core biopsy) or by surgical removal of the entire lump (excisional biopsy).
A breast biopsy during pregnancy can usually be done as an outpatient procedure. The doctor uses medicine to numb just the area of the breast that will be biopsied. There is little risk to the baby. A biopsy also can be done under general anesthesia if need, with just a small risk to the baby.
Needle biopsies are safe in women who are breastfeeding. The risk of infection is higher with excisional biopsies because more surgery is involved, and breast milk can leak into the surgery area. If this does happen, the milk can be drained by fine needle aspiration.