Reproduction Issues & Breast Cancer

Reproduction Issues Breast Cancer

Also called: Fertility and Breast Cancer, Pregnancy and Breast Cancer

Reviewed By:
Mark Oren, M.D., FACP


A growing number of women are being diagnosed with breast cancer during their child-bearing years. With these numbers on the rise, the issue of pregnancy and fertility after breast cancer is now receiving more attention.

For women who have yet to start a family when breast cancer is detected, this concern can add extra impact to an already difficult diagnosis. Despite promising studies, there are risks to be considered when planning a pregnancy after breast cancer treatment.

Virtually all hormonal events in a woman’s life, including age at menarche (onset of a woman’s first period) and age at first full-term pregnancy are considered risk factors in the development of breast cancer. Some of the reproductive issues related to the disease include:

  • Loss of fertility. Infertility from treatment can occur, either due to menopause induced by chemotherapy or damage to ovaries from radiation therapy or drugs. Induced menopause may be temporary and precautionary measures can be taken to protect the ovaries.
  • Breast cancer during pregnancy. A small, but growing number of women are diagnosed during pregnancy or while breastfeeding. For some, special considerations will need to be factored into treatment protocols.

Fertility issues and breast cancer

Following treatment for breast cancer, the loss of fertility is a possibility. Whether or not a woman begins menstruating again after treatments will depend on her age and the types and doses of chemotherapy and/or other adjuvant treatments she receives.

It is common for a premenopausal woman to enter menopause – either temporarily or permanently – from chemotherapy treatments. Menopause includes a wide variety of changes that a woman undergoes as she stops menstruating. Common menopausal symptoms, which may be brought on by chemotherapy, include:

  • Hot flashes, including night sweats and sleep disturbance

  • Emotional changes such as depression or mood shifts

  • Vaginal changes such as dryness that can result in uncomfortable or painful sexual intercourse

  • Sexuality changes, including a decrease in desire

  • Weight gain

A woman who is treated for breast cancer often faces the possibility of several long-term side effects from treatment. However, each person and prognosis is different,depending on number of factors. Women diagnosed with breast cancer who wish to have children after treatment should speak to a fertility specialist in addition to her oncologist before making treatment decisions.

Some chemotherapy drugs have a more adverse affect on fertility than others. Most women who have not yet undergone menopause will have irregular menstrual cycles or may experience a total disappearance of periods (amenorrhea). Women who do begin menstruating again after treatment are at a higher risk of entering menopause early than women who did not undergo treatment for breast cancer.

Menopause that is brought on by chemotherapy can start immediately with treatments or be delayed. It may be permanent or temporary (as short as a few months or as long as a few years). Many premenopausal women retain or recover functioning of the ovaries and menstruation once their treatment is complete. However, complete recovery of ovarian function may depend on the woman’s age and the type of chemotherapy drugs that were used in her treatment. Certain chemotherapy treatments may be able to reduce the risk of permanent menopause.

Some research has suggested that certain drugs such as goserelin and leuprolide may help protect a woman’s ovaries during chemotherapy treatments. These drugs may help prevent the chemotherapy drugs from attacking healthy cells in the ovaries while destroying cancer cells. More research is needed to determine if these drugs truly protect the ovaries and if they improve the chances of developing regular periods after chemotherapy. Women with certain forms of breast cancer also may be treated with hormonal therapy, such as tamoxifen. Hormonal therapies prevent cancer from receiving necessary hormones that help it to grow. Tamoxifen, like chemotherapy, can affect the ovaries, causing irregular menstrual periods or no periods at all. However, with tamoxifen, women usually return to regular menstrual cycles.

Taking tamoxifen for the standard five-year period, however, does reduce a woman’s time frame for having children. Patients taking the drug are advised not to become pregnant due to its risk for birth defects. For many women, waiting five years to become pregnant may not be a realistic possibility.

Women with breast cancer who are facing infertility may be able to preserve their fertility by storing embryos. This procedure is performed by collecting eggs from a woman during several menstrual cycles. The eggs are then fertilized by sperm and stored at a low temperature. After the woman has finished her cancer treatments, the embryos can be thawed and implanted in the uterus.

A more experimental method of preserving fertility involves collecting a woman’s eggs and storing them unfertilized. After treatment, the eggs are fertilized and implanted in the women’s uterus. This technique has proved to be less successfully in resulting in pregnancy and is usually recommended for women enrolled in a clinical trial on the procedure.

Radiation therapy as a form of treatment also may affect fertility. It is important for women to speak with their cancer care team and obstetrician-gynecologist if a family is being considered. For women who still wish to have children following treatment for breast cancer, there is a risk of damage to the ovaries from radiation. Precautionary measures should be taken if possible to protect the ovaries as well as the other breast.

Surgery, such as mastectomy, rarely has any bearing on whether or not a woman can later become pregnant. Women who are considering reconstructive surgery of the breast using part of the abdominal muscle(s) may want to consult with their physician. It may be contraindicated for someone who wishes to later become pregnant.

For women still in their childbearing years, it is extremely important to discuss birth control with the oncologist because both chemotherapy and radiation can lead to severe birth defects if a woman becomes pregnant during treatment. Safe and effective birth control can include the use of barrier contraceptives such as diaphragms or condoms.

Certain types of breast cancer are closely associated with hormones for growth and development. For that reason, birth control pills are normally not recommended for breast cancer patients. Also, since there is an established link between estrogen levels and the growth of breast cancer, hormone replacement therapy (HRT) may not be recommended for breast cancer survivors. For women who were already taking HRT prior to their diagnosis, stopping this therapy can lead to menopausal symptoms. It is important for breast cancer patients to discuss all hormone related issues with her cancer care team physicians.

Pregnancy and breast cancer recurrence

Because most cases of breast cancer occur in older women, reproduction issues are often not a concern. Women over 50 account for more than 75 percent of all breast cancer diagnoses, according the American Cancer Society (ACS). Still, the ACS reports that nearly 12,000 women under the age of 40 are diagnosed with invasive breast cancer each year. Women who are under the age of 40 have a 1 in 68 chance of developing the disease.

For many of these young women diagnosed with breast cancer, reproduction issues are very much in mind as they enter treatment. If they plan on having children, they may be concerned about whether estrogen levels will encourage the cancer to return, following treatment.

During pregnancy, total estrogen levels are 1,000 times that of a menstruating woman. In the past, physicians advised breast cancer patients that becoming pregnant may pose a serious risk to their lives since estrogen levels are elevated for an extended period of time during pregnancy.

If a tumor is found to be estrogen-receptor positive, then the presence of estrogen may cause any remnants of the tumor to grow. However, most studies have found that a pregnancy after breast cancer does not increase the chances of a recurrence despite the increased estrogen levels. Recent studies on patients with subsequent pregnancies seem to indicate that there is little or no difference in long-term survival rates.

In fact, in one study conducted at The Fred Hutchinson Cancer Research Center in Washington, results revealed that women who became pregnant after treatment had slightly better survival rates and longer disease-free intervals when cases of recurrence were compared against a control group.

The ACS recommends waiting five years before becoming pregnant if the cancer tumors are particularly large or aggressive, or if a number of lymph nodes have had evidence of cancer. In these cases, the cancer has a greater chance of spreading to other areas of the body. When tumors are small and lymph nodes are not involved, the ACS recommends waiting two years following treatment.

Breast cancer patients should consult with their physician regarding their prognosis and how long they should wait before becoming pregnant based on their individual diagnosis and treatment plan. The discussion should include the possibility of recurrence, the possibility of damage to her ovaries from radiation treatment, possible heart damage from chemotherapy drugs and any other health-related matter that could be exacerbated by pregnancy.

Issues during pregnancy with breast cancer

According to the American Cancer Society (ACS), approximately 3 to 7 percent of all breast cancer diagnoses take place in women who are pregnant or breastfeeding. Although it is the most common form of cancer in pregnant women, it is diagnosed in just 1 pregnancy out of every 3,000, according the ACS.

Breast cancer in itself does not appear to harm the fetus, as long as the mother’s health remains good. In other words, the cancer can not be transmitted to the fetus. In addition, there is no evidence that a history of breast cancer in a woman has any effect on her baby.

According to the National Cancer Institute (NCI), the average age of a breast cancer patient who is diagnosed during pregnancy or while still breastfeeding, is between 32 and 38 years of age. Thus, with more and more women choosing to delay childbearing, the number of pregnant or postpartum women diagnosed with breast cancer is expected to rise.

During pregnancy, total estrogen levels are 1,000 times that of a menstruating woman. The body’s additional exposure to all the estrogen, in turn, can cause cancer to grow and multiply even faster. For this reason, there are additional factors to be taken into consideration for treatment of a pregnant woman with breast cancer.

Breast cancer diagnosed during pregnancy is often detected at a later stage due to the natural enlargement of the breasts, which makes it more difficult to find or notice changes. These risks to both mother and child make it imperative to make clinical breast exams part of the prenatal and postnatal care. 

According to the ACS, it is relatively safe for women to have mammograms during pregnancy. The amount of radiation is low and is focused on the breast tissue. A lead shield that covers the abdomen is used for extra protection. Because researchers still do not know for certain the effects of low dose radiation on the fetus, a woman’s physician can best determine if the mammogram must be performed immediately or if it can wait until after the baby is born. In some cases, the physician may choose another imaging test, such as breast ultrasound, that does not use radiation.

If an abnormal area or lump is detected, a biopsy is necessary to definitively diagnosis cancer. The procedure removes a sample of tissue from the suspected area, typically using local anesthesia that numbs the area. It is usually performed on an outpatient basis with little risk to the fetus. If the biopsy needs to be completed with the woman asleep (general anesthesia), it is still considered to be relatively safe for the unborn baby.

For pregnant women with breast cancer, the type of treatment, as well as the schedule, depends on multiple factors. Whenever possible, surgery is typically the first choice of treatment for breast cancer in all women. The primary goal is to control the cancer and keep it from spreading (metastasizing) in the body.

Traditional breast cancer treatments such as lumpectomy, mastectomy and/or removal of the lymph nodes can be considered in pregnant women. These procedures are completed under general anesthesia, which may pose a higher risk to the fetus. The patient’s cancer care team and obstetrician will need to determine the safest treatment method and timing for the surgery.

Breast conserving surgeries, such as lumpectomy, typically require radiation therapy after surgery to prevent the cancer from returning. Since radiation can harm the fetus, this treatment would need to be delayed until after the birth of the baby. Studies have not proven how this delay affects the risk of cancer recurrence and the patient’s prognosis. For this reason, women may choose mastectomy which typically does not require radiation therapy.

Based on the results of several studies, chemotherapy may be considered during the second and third trimesters of the pregnancy (fourth through nine months of pregnancy), but not during the first trimester (the first three months), according to both the ACS and the NCI. Chemotherapy treatments during the last two trimesters has not been found to increase the risk of birth defects or stillbirths. However, scientists do not yet know the long term effects of chemotherapy on these children.

Women who undergo breast cancer surgery in their third trimester may have their chemotherapy treatment delayed until after birth. In these cases, the baby may be delivered a few weeks early to begin earlier treatment.

Due to the potential side effects from chemotherapy, treatments should not be given three to four weeks before delivery, according to the ACS. The drugs can result in bleeding and increase the risk of infection. During this time period, chemotherapy is withheld to allow the mother’s blood count to increase and return to normal.

The effects of hormone therapy (e.g., tamoxifen) have not been widely studied in pregnant women. Some research has indicated a specific defect may occur in the fetuses of women who become pregnant while taking tamoxifen. Animal studies also have found that tamoxifen may cause fetal changes. Hormone therapy currently is not recommended for treatment of breast cancer in pregnant women and should not be used until after the birth of the baby.

For women diagnosed with breast cancer who are still breastfeeding, it is advisable for them to stop nursing once treatments begin. Chemotherapy drugs can be passed to the baby through the mother’s breast milk. After treatments have stopped, a woman should discuss with her physician when it might be safe to resume breastfeeding.

While some physicians may recommend terminating an early pregnancy to begin treatment, studies have shown that terminating the pregnancy does not improve a woman’s survival rates. Breast cancer treatments during pregnancy depend on how far along in the pregnancy it occurs and the size, location and stage of the breast cancer. A diagnosis of breast cancer during pregnancy may correlate to lower overall survival rates for the mother due to a number of factors. Additional research is being conducted on treatment methods and timing to improve the prognosis for pregnant women with breast cancer.

Questions for your doctor

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Women may wish to ask their doctor the following questions about reproduction issues and breast cancer:

  1. What type of tests can I receive if I am pregnant?

  2. How will my breast cancer and treatment affect becoming pregnant?

  3. Will these treatments cause permanent or temporary menopause?

  4. Is there a way to prevent menopause from the treatments?

  5. Should I consider preserving my eggs before treatment?

  6. After treatment, when can I start planning a family?

  7. What type of birth control should I use during this time?

  8. What are the breast cancer treatment options during my pregnancy?

  9. How will pregnancy affect my prognosis?

  10. Will pregnancy increase my chances of breast cancer recurrence?

  11. Will I be able to breastfeed after my treatments?
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