Childhood years and breast cancer.

What can impact my child's breast cancer risk later in life?

The newborn stage, childhood and teenage years are periods of intense growth and development, meaning they may be more susceptible to the effects of endocrine disrupting chemicals (EDCs). Exposure to EDCs while a child is growing may change how their body develops and increase their risk of breast cancer when they are older.

So far, studies have been limited. More research is needed.

Key facts about the effects of EDC exposure in children.

• A possible link between the effects of EDC exposure in the newborn and the development of the brain has been noted in some studies. However, more research is needed in this area.
• Some EDCs may be found in breast or formula milk.
• Your child may be exposed to chemicals through hand-to-mouth behaviours, from things like plastic toys, which they put in the mouth and dust, which accumulates on their hands when crawling around.
• Puberty is a period of significant growth and development, which may make us more susceptible to EDCs.
• During puberty, the female body undergoes significant changes, with the breasts developing to maturity and the menstrual period commencing.
• Females who start puberty before eight years old have an increased breast cancer risk. 
• The link between exposure to EDCs and the age at which puberty starts is still unclear.
• Hormonal contraceptives, such as “the pill”, can slightly increase breast cancer risk.

Why are newborn and younger children more vulnerable to chemical exposure?

Newborns and young children are more vulnerable to chemical exposure because their bodies are still developing, they have different behaviours, and they have a higher rate of exposure to chemicals relative to their body weight compared to adults. 

The periods of rapid growth and development during these years are critical "windows of susceptibility" where even low-level exposure to chemicals may cause damage to cells. 

Hand-to-mouth exploratory behaviours exhibited by children at this age can increase their exposure to EDCs. These chemicals can also accumulate in dust, which children are exposed to when crawling or playing on the floor.

Children may have higher levels of EDCs in their bodies because they eat, drink and breathe more relative to their body weight compared to adults.

During these periods, the breast undergoes extensive development. Research suggests that exposure to harmful chemicals such as EDCs during these critical periods may adversely affect normal development. 

Teenage years and breast cancer risk.

Is there a link between the age at puberty and breast cancer risk?

Starting menstrual periods early (before 10 years old) and developing breasts early (before eight years old) have been linked with an increased risk of breast cancer.

Studies have shown that girls are now starting puberty at a younger age than girls who were born in the 1970s. With puberty starting at a younger age, the exposure to oestrogen throughout life is lengthened. 

Prolonged exposure to oestrogen is believed to increase breast cancer risk.

What is puberty?

Puberty is a time of significant growth and physical changes. It usually starts between eight and 13 years old for females and between nine and 14 years old for males.

What are the main changes in females during puberty?

The start of menstrual periods and the development of the breasts are the main changes in females. These are controlled by hormones, mainly oestrogen.

Endocrine Disrupting Chemicals (EDCs) can interfere with the normal function of hormones and may have an impact on puberty and breast development.

Does exposure to EDCs during puberty affect breast cancer risk?

So far, studies have mainly focused on how EDCs affect the age at which puberty starts, as earlier puberty has been linked to an increased breast cancer risk. However, so far, research has been inconclusive. 
 
During puberty, the breast undergoes extensive development and may be more vulnerable to the effects of EDCs, which could affect the risk of breast cancer in the future.  

More research is needed to explore the link between EDC exposure and puberty and how this may affect breast cancer risk.

Do oral contraceptives increase breast cancer risk?

Studies have shown that taking the combined contraceptive pill (the pill) slightly increases breast cancer risk. This risk is no longer evident 10 years after use has stopped.

Other studies suggest that progestogen-only oral contraceptives (mini-pill) may not be associated with breast cancer risk; however, a study from 2023 has shown a small increase in risk.

Are other types of hormonal contraceptives linked to breast cancer?

Other types of hormonal contraceptives include patches and vaginal rings, which use both oestrogen and progestogen. Injections, implants and intrauterine devices (IUDs, such as the Mirena coil) contain only progestogen.

Fewer studies have looked at the link between these types of contraceptives and breast cancer risk. However, the risks for some of these (progestogen-only) may be similar to those associated with oral contraceptives.

Start your prevention journey today.

To begin reducing your exposure to harmful chemicals for you and your child, choose one of these actions to commit to this week:

• Swap plastic water bottles and lunch boxes for stainless steel: avoid putting hot foods/liquids in plastic, and switch plastic water bottles, storage containers, and lunch boxes to glass or stainless steel alternatives.
• Regularly damp-dust, vacuum, and open your windows daily, even for just a few minutes: EDC particles can settle in house dust. Removing this dust and ventilating the room with fresh air significantly reduces your overall chemical exposure. Download our free Guide to EDCs for further tips on how to reduce your exposure to EDCs in your home.
• Use 'fragrance-free' personal care and cleaning products: replace personal care items (like shampoo, body wash, lotion) and household cleaners that list fragrance or parfum with products labelled 'fragrance-free' or those scented only with essential oils.

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.