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In vitro fertilization (IVF) is one option for people experiencing fertility challenges who want to become pregnant. Because IVF involves hormonal treatments, you may wonder whether it affects your breast cancer risk, as other types of hormone therapy can. Researchers have also questioned this relationship. However, current research shows IVF doesn’t lead to a significant increase in a person’s risk for breast cancer.
Continue reading to learn about research into IVF and the risk of breast cancer.
IVF is a type of assisted reproductive technology that can help some people conceive (become pregnant). It’s a treatment for infertility — defined as the inability to become pregnant after at least one year of trying. IVF can also be used for fertility preservation for younger people facing cancer treatment, allowing some to attempt pregnancy after completing breast cancer treatment.
IVF isn’t just one procedure. It’s a series of procedures known as an IVF cycle. Several steps make up one IVF cycle. Sometimes several IVF cycles are needed to become pregnant.
Ovarian stimulation for in vitro fertilization involves stimulating the ovaries to produce multiple eggs. Typically, the ovaries release one egg per menstrual cycle. However, in IVF, fertility medications encourage the ovaries to produce multiple eggs at once. These medications include laboratory-made versions of different hormones, including:
Sometimes, a drug called clomiphene citrate (Clomid) is used to stimulate the body to make more of its own follicle-stimulating and luteinizing hormones.
Once ovarian stimulation is complete, a healthcare provider retrieves the eggs from the ovaries using a thin needle. This procedure is typically done under sedation or anesthesia.
Fertilization involves mixing the egg and sperm in a petri dish. Fertilization happens when the sperm enters the eggs, forming an embryo. The embryos are left to grow in a controlled environment for a few days.
During the embryo transfer step, one or more embryos are placed into the uterus with the hope of achieving pregnancy.
The connection between breast cancer risk, pregnancy, and fertility is complex. Several fertility- and reproduction-related factors have been linked to changes in breast cancer risk.
Factors associated with an increased risk of breast cancer include
Conversely, having multiple pregnancies and giving birth at a younger age has been associated with a lower overall risk of developing breast cancer. However, for about 10 years after childbirth, breast cancer risk is slightly higher before it decreases over time.
Recent research suggests that infertility may be another reproductive risk factor. A 2024 study found that women with a history of infertility may have a slightly higher risk of breast cancer after menopause. Researchers believe this increased risk is largely due to delayed childbearing, as age at first pregnancy is a well-established breast cancer risk factor.
IVF is often used as the main infertility treatment for people over 40. Because of this, it may be difficult to tell if there’s a higher risk of breast cancer due to IVF treatment or older maternal age. More research is needed to better understand this relationship.
When considering breast cancer risk, the main concern with IVF is the use of hormonal medications. Researchers already know that longer lifetime exposure to hormones like estrogen and progesterone is linked to a higher breast cancer risk. Longer exposure to these hormones is linked to the reproductive risk factors for breast cancer.
IVF treatment temporarily increases the levels of estrogen and progesterone hormones in the body. This is why researchers began to investigate the connection between IVF treatment and breast cancer risk. Over the years, different studies have had conflicting results. Some studies have found an increased risk of breast cancer, while others found a decreased risk.
A 2022 study analyzed the results of 25 different studies on the effect of fertility treatments on breast cancer risk. Researchers found that fertility treatments didn’t increase the risk of breast cancer. In this study, the risk of breast cancer didn’t increase when women had six or more IVF cycles. Additionally, researchers found that taking fertility drugs wasn’t associated with an increased risk of breast cancer. However, another study found that using clomiphene citrate for more than 10 IVF cycles may increase breast cancer risk.
Similar results have also been found in individuals with genetic mutations (changes) that make them more susceptible to cancer. People with mutations in the BRCA1 or BRCA2 gene have a significantly higher risk of developing breast cancer. A 2022 study found that fertility treatment didn’t increase the risk of breast cancer in this group, either. However, more research is needed to study the effect on other types of breast cancer.
Although there have been conflicting studies in the past, health experts believe that IVF doesn’t significantly increase the risk of breast cancer. The American Society for Reproductive Medicine’s guidelines on fertility drugs and cancer state that there doesn’t appear to be an increased risk of breast cancer associated with assisted reproductive technology.
There is some evidence that IVF treatment may increase the risk of developing ovarian cancer. Researchers don’t know yet how much — or for whom — IVF might increase ovarian cancer risk. So far, it’s thought the increase in risk is likely small. More studies are needed to confirm and learn details about this connection.
The BRCA1 and BRCA2 mutation also increases the risk of ovarian cancer. People with a BRCA1 or BRCA2 mutation should discuss the increased risk of ovarian cancer with IVF with their fertility specialist.
For younger people with a breast cancer diagnosis, assisted reproductive technology such as IVF can help preserve fertility and provide options for having children after treatment. Several breast cancer treatments, including chemotherapy, can affect ovarian function, potentially leading to early menopause or reduced fertility.
Researchers questioned whether the fertility drugs used for ovarian stimulation may increase the risk of breast cancer recurrence (returning after treatment). Due to this perceived risk, some people with a genetic mutation in the BRCA1 or BRCA2 gene aren’t offered fertility preservation treatment.
However, a 2024 study found that using assisted reproductive technology didn’t increase the risk of breast cancer recurrence in young women diagnosed with breast cancer and a BRCA1 or BRCA2 mutation.
It’s estimated that about 1 in 8 women in the United States will develop breast cancer at some point in their lives. Some people have a higher or lower risk of breast cancer based on their unique genetic and environmental risk factors.
Your reproductive history is just one piece of your total risk of breast cancer. There are many other factors to consider to understand your risk of developing breast cancer, such as:
It’s natural to wonder what might raise or lower your breast cancer risk. Can breast asymmetry increase it? Can breast reduction surgery reduce it? But it’s important to remember that people with no known risk factors can also develop breast cancer. In fact, up to 70 percent of people with breast cancer don’t have any risk factors. If you’re concerned about your risk of developing breast cancer, or your risk of breast cancer coming back, follow up with your healthcare provider.
MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 77,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.
Have you had IVF? Did your fertility specialist discuss how it might affect your risk for developing potential health conditions? Share your thoughts in the comments below, or start a conversation by posting on your Activities page.
Maybell Nieves, M.D.
graduated from Central University of Venezuela, where she completed medical school and general surgery training.
Learn more about her here.
Amanda Jacot, Pharm.D
earned a Bachelor of Science in biology from the University of Texas at Austin in 2009 and a Doctor of Pharmacy from the University of Texas College of Pharmacy in 2014.
Learn more about her here.
