Pregnancy, your developing baby and breast cancer.
What is the link?
Does pregnancy affect my breast cancer risk?
Pregnancy has a complex effect on breast cancer risk: it lowers long-term risk if the first pregnancy is before age 30, but increases the short-term risk at any age. This increased risk peaks at around five years after childbirth before gradually declining but lasts for around 24 years.
Women who give birth aged 35 or older have a long-term increased risk of breast cancer compared to those who gave birth at an earlier age or who have never given birth.
Tips for reducing your risk during pregnancy.
Skip EDCs in your beauty routine.
Check labels. Watch out for common ingredients like parabens, phthalates (often hidden in fragrance or parfum).
Swap plastic for glass and steel.
Use a glass or stainless-steel reusable water bottle. Avoid pre-packaged food and store your food in glass containers.
Reduce pesticide expsoure.
Avoid using pesticides in your garden. Wash fresh fruit and vegetables before eating. If you can, buy organic food.
Key facts about pregnancy and breast cancer risk.
- Being pregnant for the first time before 30 years old reduces your long-term breast cancer risk.
- While pregnant, you may be more susceptible to Endocrine Disrupting Chemicals (EDCs).
- Pregnant people have higher levels of bisphenol A (BPA) in their bodies due to their higher food and drink consumption.
- The risk of EDC exposure is not limited only to you. EDCs can cross the placenta and may reach your baby.
- Your unborn baby in the womb may be highly susceptible to Endocrine Disrupting Chemicals (EDCs), which could cause health problems. Some of these may only become evident later in life.
- Exposure in the womb to certain EDCs may cause an increased breast cancer risk later in life.
Does the breast change during pregnancy?
During pregnancy, the structures of the breast responsible for producing milk are significantly expanded in preparation for breastfeeding. This process is under the control of the milk-producing hormone prolactin, as well as the hormones progesterone and oestrogen.
Can I get breast cancer while pregnant?
Pregnancy-associated breast cancer (PABC) is very rare, but possible. This is when breast cancer is diagnosed during pregnancy, or in the first year after giving birth; it occurs in approximately 1 in every 3,000 pregnancies.
Is there a link between exposure to EDCs during pregnancy and breast cancer?
Exposure to certain chemicals in the womb may increase a person's risk of breast cancer later in life. EDCs can interfere with the body's hormones, which are crucial for normal development.
If your baby is exposed to chemicals while in the womb this may affect the development of their brain, nervous and reproductive systems and may impact their cancer risk later in life, including breast cancer risk.
One clear example is the drug diethylstilbestrol (DES), which was given to pregnant women to prevent miscarriage. The daughters of these women have a higher risk of developing breast cancer later in life.
EDCs may also indirectly increase risk by causing changes in the body, such as triggering early puberty and increased breast density, both of which are linked to a higher risk of breast cancer.
While the link between DES and breast cancer is clear, for most other EDCs, more research is needed to understand how exposure in the womb may affect breast cancer risk later in life.
However, we already know that drinking even small amounts of alcohol whilst pregnant can affect the health of your unborn baby.
Alcohol can cross the placenta and may affect the brain and physical development of your baby. This is known as Foetal Alcohol Spectrum Disorder (FASD).
We therefore recommend that a precautionary approach be taken to reduce your exposure to harmful chemicals whilst pregnant.
Studies are also needed to find out if there is a link between EDC exposure during pregnancy and breast cancer risk in the mother.
Why is my developing baby highly susceptible to chemicals?
In the womb, your developing baby is more susceptible to harmful chemicals because the system that our body uses to eliminate toxins and chemicals only develops after birth. For this reason, even low levels of chemicals that are considered safe in adults may be harmful to a developing baby in the womb.
How EDCs reach the baby.
How do EDCs reach my baby?
During pregnancy, you can be exposed to EDCs from various sources, including food and water. When these chemicals enter your blood, they can cross the placenta, which is the organ that provides oxygen and nutrients to the baby.
The placenta acts as a partial barrier, stopping some substances from crossing it while allowing other chemicals to pass through and reach your baby.
EDCs have been found in the amniotic fluid (the liquid surrounding the baby) and the umbilical cord.
Start your prevention journey today.
To begin reducing how much alcohol you drink, choose one of these actions to commit to this week:
- Minimise endocrine disrupting chemicals (EDCs) in your beauty routine: be mindful of the products you use. Check labels and try to skip EDCs in your beauty routine. Specifically, watch out for common ingredients like parabens and phthalates (which are often hidden in "fragrance" or "parfum").
- Swap plastic for glass and steel for food and drink: reduce your exposure to chemicals like bisphenol A (BPA) by switching your containers. Use a glass or stainless-steel reusable water bottle. Also, avoid pre-packaged food where possible and store your food in glass containers. Pregnant people may have higher levels of BPA due to increased food and drink consumption.
- Reduce pesticide exposure and choose organic when possible: avoid using pesticides in your garden to reduce pesticide exposure. Always wash fresh fruit and vegetables before eating, and if you can, buy organic food.
Remember, these small steps can make a big difference. Which one will you try first?
Further reading
For more information, read our Critical Windows of Susceptibility for Breast Development science review.
Last review: Oct-23 | Next review: Oct-26.
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- Chung DD, Pinson MR, Bhenderu LS, Lai MS, Patel RA, Miranda RC. Toxic and Teratogenic Effects of Prenatal Alcohol Exposure on Fetal Development, Adolescence, and Adulthood. Int J Mol Sci 2021;22. https://doi.org/10.3390/IJMS22168785.
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