BREAST CANCER AND PREGNANCY

Article from The National Cancer Institute

Breast cancer is the most common cancer in pregnant and postpartum women, occurring in about 1 in 3,000 pregnant women. The average patient is between 32 and 38 years of age and, with many women choosing to delay childbearing, it is likely that the incidence of breast cancer during pregnancy will increase. The natural tenderness and engorgement of the breasts of pregnant and lactating women may hinder detection of discrete masses, and therefore, early diagnoses of breast cancer. Delays in diagnoses are common, with an average reported delay of 5 to 15 months from the onset of symptoms. Because of this delay, cancers are typically detected at a later stage than in a non-pregnant woman of the same age. To detect breast cancer, pregnant women and lactating women should practice self-examination and undergo a breast examination as part of the routine prenatal examination by a doctor. If an abnormality is found, diagnostic approaches such as ultrasound and mammography may be used. With proper shielding, mammography poses little risk of radiation exposure to the baby. Some factors associated with pregnancy are known to reduce a woman’s chance of developing breast cancer later in life: • The younger a woman has her first child, the lower her risk of developing breast cancer during her lifetime. • A woman who has her first child after the age of 35 has approximately twice the risk of developing breast cancer as a woman who has a child before age 20. • A woman who has her first child around age 30 has approximately the same lifetime risk of developing breast cancer as a woman who has never given birth. • Having more than one child decreases a woman’s chances of developing breast cancer. In particular, having more than one child at a younger age decreases a woman’s chances of developing breast cancer during her lifetime. • Although not fully understood, research suggests that pre-eclampsia, a pathological condition that sometimes develops during pregnancy, is associated with a decrease in breast cancer risk in the offspring, and there is some evidence of a protective effect for the mother. • After pregnancy, breastfeeding for a long period of time (for example, a year or longer) further reduces cancer risk by a small amount. Some factors associated with pregnancy are known to increase a woman’s chances of developing breast cancer:  • After a woman gives birth, her risk of breast cancer is temporarily increased. This temporary increase lasts only for a few years. • A woman who during her pregnancy took DES (diethylstilbesterol), a synthetic form of estrogen that was used between the early 1940s and 1971, has a slightly higher risk of developing breast cancer. (So far, research does not show an increased breast cancer risk for their female offspring who were exposed to DES before birth. These women are sometimes referred to as “DES daughters”.) There are a number of misconceptions about what can cause breast cancer. These include, but are not limited to, using deodorants or antiperspirants, wearing an underwire bra, having a miscarriage or induced abortion, or bumping or bruising breast tissue. Even though doctors can seldom explain why one person gets cancer and another does not, it is clear that none of these factors increase a woman’s risk of breast cancer. In addition, cancer is not contagious; no on can “catch” cancer from another person. A woman can be an active participant in improving her chances for early detection of breast cancer. NCI recommends that, beginning in their 40s, women have a mammogram every year or two. Women who have a higher than average risk of breast cancer (for example, women with a family history of breast cancer) should seek expert medical advice about whether they should be screened before age 40, and how frequently they should be screened.