|Pregnant with Breast Cancer|
Finding out you have breast cancer while you are pregnant is very upsetting. You are likely to feel a range of emotions including anger, sadness or fear.
Breast cancer during pregnancy is rare, but numbers have been increasing over the past few years. Research shows that breast cancer is reported in 1 in every 3,000 pregnancies. Most women are between 32 and 38 years old at diagnosis. Most are able to carry on with their pregnancy.
Rarely, some women may need to think about whether to end the pregnancy (termination). This will be discussed with you, especially if you:
- need chemotherapy
- are less than 14 weeks pregnant
Pregnancy and breast cancer risk
Pregnancy is a time of breast development and hormone changes, so it is not surprising that it affects your breast cancer risk. However, this relationship is complex. Both the age when you give birth to your first child and the number of children you give birth to affect your risk.
How does age at the birth of a first child affect your breast cancer risk?
Although a first pregnancy may increase the short-term risk of breast cancer, it lowers the long-term risk. Pregnancy’s effects depend on your age when you first give birth.1-3
Women who have their first child at age 35 or younger tend to get an overall protective benefit from pregnancy. Breast cancer risk is slightly increased for about 10 years after a first birth. After that, it drops below the risk of women who don't have children. The younger you are when you have your first child, the sooner you get the risk reduction benefit.2-3
Women who have their first child at later ages are at an increased risk of breast cancer compared to women who have their first child at younger ages.2-3 For example, women who give birth for the first time after age 35 are 40 percent more likely to get breast cancer than women who have their first child before age 20.4 For women who give birth at older ages, the increase in risk from a first pregnancy never gets fully offset by its long-term protective benefits.2-3
Why does age at first birth matter?
The different effects of age at first childbirth on breast cancer risk may be related to breast cells. During pregnancy, breast cells grow rapidly. If there is any genetic damage in the breast cells, it gets copied as the cells grow. This increased genetic damage in the cells can lead to breast cancer. And, the chance of having such genetic damage goes up with age. This may explain why women who have their first child at a later age have a higher risk of breast cancer than women who have their first child at a younger age.1,3
How does childbearing affect your breast cancer risk?
The more children a woman has given birth to, the lower her risk of breast cancer tends to be. After a first child, each childbirth lowers risk.3 The exact reasons behind this link are unclear at this time.
Women who have never given birth (called nulliparous) have a slightly higher risk of breast cancer compared to women who have had more than one child.3 However, women who give birth only once at age 35 or older have a slightly higher risk compared to nulliparous women. This is because the excess risk of having only one child at an older age never quite goes away.2-3
Whether having children protects equally against estrogen receptor-positive and estrogen receptor-negative (including triple negative) breast cancers is under study.5 Learn more about triple negative breast cancers.
Your team will plan for you to have your baby as close to your due date as possible. Depending on your treatment plan and due date your obstetrician might induce your birth so you have a vaginal delivery. Or it may be safer to have a caesarean section.
Breast cancer has never been known to spread to a baby. The doctors will collect your placenta after birth and look at it down a microscope. It’s very rare, but cancer cells could spread there.
Your cancer doctor and midwife will let you know if you will be able to breastfeed after your baby is born. Some cancer drugs pass into the breast milk.