Late pregnancy and breast cancer: Know the connection

If you have a family history of breast cancer then it may put you at risk. Apart from genes, there are other factors that can increase your chances of developing this form of cancer that mostly affects women. One of them is having children at a later stage in life. You may decide to focus on your professional life or other responsibilities in your 20s. However, women who have their first child after the age of 30 may be at a greater risk of developing this disease. On the occasion of National Cancer Awareness Day, which is observed on November 7 in India, know how late pregnancy can increase breast cancer risk.

What is breast cancer?

It is a type of cancer that develops in the cells of one or both of your breasts and is characterised by the uncontrolled growth of breast cells that can form a tumour. These tumours can be benign (non-cancerous) or malignant (cancerous), with malignant ones having the potential to invade surrounding tissues. Around 2.3 million women across the globe were diagnosed with this disease in 2022, and 670,000 of them died in that year, according to the World Health Organization.

Risk factors of breast cancer

Certain factors increase the risk of this type of cancer including:

• Increasing age
• Obesity
• Too much alcohol consumption
• Family history of breast cancer
• History of radiation exposure
• Tobacco use
• Postmenopausal hormone therapy

Symptoms of breast cancer

Early-stage breast cancer may not present noticeable symptoms, which is why regular screenings are essential. However, as the disease progresses, these symptoms may occur –

• Lump in the breast or underarm area that feels a little different from the surrounding tissue. They can be painless, hard, or soft.
• Changes in breast size or shape
• Dimpling of the breast skin.
• A rash on or around the nipple.
• Nipple discharge, which can be clear or bloody.
• Pain or tenderness in the nipple.

Late pregnancy and breast cancer: Know if it is a risk factor

Late pregnancy refers to a pregnancy that occurs when a woman is in her late 30s or 40s. “Pregnancy at a later age is linked to health risks, including a higher risk of developing breast cancer,” says gynaecologist and infertility expert Dr Gurpreet Batra. Female gender is the strongest risk factor, with approximately 99 percent of breast cancers occurring in women, according to the World Health Organization (WHO). But having the first pregnancy after age 30 is a risk factor for breast cancer you can change, according to the US Centers for Disease Control and Prevention.

A study published in BMC Women’s Health in May 2024 showed that the average delivery age has shot up from 27 to 35 years in the last 30 years. Researchers also found that the overlap between breast cancer diagnosis and increasing maternal age had gone up by almost 200 percent. Here’s how late pregnancy and breast cancer may be linked:

1. Hormonal changes

Throughout a woman’s reproductive years, her breast tissue is exposed to the hormones estrogen and progesterone, which play essential roles in the menstrual cycle and pregnancy. “Higher lifetime exposure to the estrogen hormone has been linked to an increased risk of this type of cancer. Pregnancy and breastfeeding temporarily reduce exposure to this hormone, offering some protective effects. Women who have their first full-term pregnancy at a younger age experience this protective phase sooner. However, those who delay pregnancy remain exposed to it for a longer duration, potentially raising their risk,” says Dr Batra.

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2. Incomplete breast cell differentiation

“Breast cells become fully mature and differentiated while expecting, particularly after the first full-term pregnancy, which makes them less susceptible to cancerous changes,” says the expert. Women who experience their first full-term pregnancy later in life have spent more years with breast cells in a less differentiated, and potentially more vulnerable state. The longer these cells remain in this undifferentiated state, the greater the risk of mutations leading to cancer.

3. Increased number of menstrual cycles

The total number of menstrual cycles a woman experiences is an important risk factor. Each cycle subjects the breast tissue to hormonal changes, and women who delay pregnancy may experience many more cycles over their lifetime. This repeated hormonal stimulation can contribute to breast tissue changes associated with cancer risk.

4. Late pregnancy and breast density

Breast density is a recognised risk factor. “Breast density often increases during late pregnancies, and so, can make cancer detection more challenging in mammograms,” says the expert. It may elevate this cancer risk due to the greater amount of glandular tissue in the breasts.

“While there may be a link between late pregnancy and breast cancer, you need to know that not all women who deliver children later in life will develop the disease,” says Dr Batra. Many risk factors, including genetics, lifestyle, and overall health, play a crucial role.

Late pregnancy and breast cancer: Treatment options

Treating breast cancer in women who had a late pregnancy follows general breast cancer treatment principles. Here are the main treatment approaches –

1. Surgery

Surgery may involve either a lumpectomy (removal of the tumour and a margin of surrounding tissue) or a mastectomy (removal of the entire breast). Women who had a late pregnancy may have denser breast tissue, which can make surgery and preoperative imaging more complex. “Skilled imaging techniques are often necessary to accurately determine the tumour’s location and ensure complete removal,” says the expert.

2. Radiation therapy

Radiation therapy is typically recommended after a lumpectomy to destroy any remaining cancer cells in the breast area. Women in 30s Or 40s may experience different skin sensitivities and recovery times due to changes in skin elasticity and resilience with age.

3. Hormone therapy

This type of cancer is usually hormone receptor-positive, meaning it grows in response to estrogen or progesterone. Hormone therapy, such as tamoxifen or aromatase inhibitors, helps block the hormones and slow or stop cancer growth. Women who get pregnant later in life often have hormone-sensitive tumours, making hormone therapy particularly effective.

4. Chemotherapy

Chemotherapy is a treatment used to target rapidly dividing cancer cells and is recommended if the cancer is aggressive or has spread beyond the breast. Women who had a late pregnancy may face unique health challenges with chemotherapy, as it can be harder for the body to tolerate the drugs with age. “Dose adjustments and supportive treatments like anti-nausea medications, immune support are often tailored to improve tolerance and recovery,” says Dr Batra.

5. Immunotherapy

Immunotherapy works by helping the immune system spot then attack cancer cells. Age-related immune function may impact the effectiveness of immunotherapy in women in their 30s or 40s, so treatment is often individualised and combined with other therapies to improve outcomes.

Late pregnancy and breast cancer may be connected, but just because you decide to have a baby after 30 does not necessarily mean you will end up with this disease. Maintain a healthy weight by exercising regularly and eating healthy to lower risk. Go for routine mammograms and breast exams in a clinic or hospital, as they can help detect breast cancer early when it is most treatable.