The decision to undergo IVF can be quite overwhelming for women. You may have countless questions about what happens during different stages of IVF, how you can prepare, what the success rates are, and how IVF pregnancies continue.
Among these, one of the most worrying questions you may have is: Can IVF raise your risk of cancer? Research shows no link between assisted reproductive technology and a woman’s risk of developing cancer.
The incidence of ovarian and thyroid cancers in women undergoing IVF can be slightly higher, but whether this increased risk is solely because of fertility drugs remains unclear. The underlying fertility issues, such as PCOS, endometriosis, and other hormonal imbalances, can contribute to the elevated risk.
It’s important to understand the connection between the two findings. A woman who’s undergone IVF can develop cancer in the future, but that doesn’t mean it’s because of fertility treatments. They may have existing medical conditions that raise their risk.
Understanding IVF and How It Works
In-Vitro Fertilization (IVF) is a popular Assisted Reproductive Technology that helps couples struggling with infertility conceive. It’s recommended for women who can’t get pregnant naturally because of endometriosis, blocked fallopian tubes, or uterine anomalies, as well as for male-factor infertility.
It’s also an effective method of conception for couples who want to preserve their fertility by freezing their gametes or those who want preimplantation genetic screening to test the developing embryo for chromosomal defects.
Steps Involved in IVF
Step 1: Ovarian Stimulation
Hormonal injections stimulate your ovaries to grow multiple follicles containing eggs. These injections are administered for 8-14 days, depending on how your ovaries respond. They can be self-administered into your lower belly.
You need to visit the fertility clinic every 2-3 days (or as frequently as your doctor requires) for blood and ultrasound scans. These are used to track follicular growth. Once the follicles have reached the desired size, a final trigger shot is used to mature the eggs and prepare them for retrieval.
Step 2: Egg Retrieval
After the trigger shot, you visit the clinic again for egg pickup — a short procedure where mature eggs are collected by passing a fine needle through the vagina into the ovaries.
The follicular fluid is then aspirated with gentle suction. On average, 8-15 eggs are collected in a single IVF cycle, although the exact number can be higher or lower, depending on your ovarian reserve and how your ovaries respond to stimulation.
Step 3: Fertilization in the Laboratory
If you are using fresh sperm, your partner is required to deliver a sperm sample on the same morning as your egg retrieval. The sperm is prepared and placed with the eggs in a culture dish, and is left overnight for fertilization.
Alternatively, ICSI may be needed for those with previously failed IVF cycles or severe male-factor infertility. This advanced fertilization technique involves manual injection of sperm into healthy eggs.
Step 4: Embryo Culture
Within approximately 17 hours of sperm and egg combining, the egg will be fertilized and begin to develop into an embryo. The embryo is cultured in a special incubator that’s optimized to provide an ideal environment for growth.
The embryologist monitors these embryos until they develop into a 100-cell structure by day 5-6. The main aim is to transfer a properly developed, strong embryo at a blastocyst stage to maximize the chances of implantation.
Step 5: Embryo Transfer
Once the embryos are prepared, they are transferred into a small flexible tube, which is inserted into the vagina. It’s a short 5-10 minute outpatient procedure. Through this catheter, they will release the embryo into the uterus. There you go!
The embryo is successfully transferred into the uterus. There’s no anesthesia required, no hospital stay usually, and you can walk around or perform light activities like normal.
Step 6: Pregnancy Testing
The last step is testing for pregnancy. You can do it at home with a simple home pregnancy test or visit your fertility clinic for a blood test that measures your hCG levels.
Why Fertility Medications Are Used
Hormonal medicines are needed mainly during ovarian stimulation. The type and dose of drugs administered can vary between clinics and women, and it depends on your underlying infertility causes.
These drugs include Clomiphene citrate (Clomid) and letrozole (Femara), Follitropin alfa (Gonal-f) and follitropin beta (Follistim), and Menotropins (Menopur), which contain follicle-stimulating hormone (FSH) and Luteinizing Hormone (LH) that encourage your ovaries to produce multiple follicles in a single ovulatory cycle.
Sometimes, ovulation suppression medicines may be used to prevent premature ovulation. Lastly, trigger shots that mature the developing egg are administered once the follicle has reached a certain size.
Why Is There Concern About Cancer and IVF?
Since IVF involves multiple fertility injections and oral medicines, many people have wondered if there’s any link between changes in reproductive hormones and the woman’s risk of developing cancer. Let’s see why it raises concerns.
The Hormone Connection
Certain cancers have hormone receptors, meaning a rise in reproductive hormones, especially estrogen, can influence their growth. Normally, estrogen levels increase when an egg develops, in order to thicken the endometrium for a potential implantation.
In IVF, repeated exposure to ovarian stimulation medicines and multiple follicles growing in the ovaries can cause a spike in estrogen, which is much higher than the estrogen spike in a regular menstrual cycle.
This raises a question: can a rise in estrogen increase breast, ovarian, or uterine cancers risk. Note that increased estrogen alone is rarely responsible for increased risk of hormone-sensitive cancers.
It’s usually a combination of environmental, reproductive, lifestyle, and genetic factors that influence the risk. For example, in many women, infertility itself, fewer children, or conceiving late in life can affect the risk.
Early Studies and Public Concerns
A common factor that has raised concerns is the earlier studies. They produced mixed results, with some studies linking IVF with a heightened cancer risk, while others found no connection between the two. The difference here is the comparison group.
Women who conceive without medical assistance are different from those who need fertility treatments in the first place. For example, women struggling with PCOS-related infertility already have a high cancer risk compared to those with no reproductive concerns.
PCOS increases estrogen, thickening the uterine lining without enough progesterone to balance it. Repeated and long-term exposure to this hormonal fluctuation can increase the risk of endometrial cancer. Likewise, endometriosis can cause ovarian cancer.
The existing hormonal condition makes fertility treatment and cancer research difficult to understand. Besides, cancer takes several years to develop, thus requiring years, sometimes decades, of follow-up.
Does IVF Increase the Risk of Breast Cancer?
During IVF, estrogen and progesterone levels increase drastically. And certain breast cancer cells use these reproductive hormones to grow. However, newer studies have shown that the brief hormonal exposure doesn’t necessarily increase breast cancer risk.
According to Breastcancer.org, 75% of breast cancers grow using estrogen and progesterone. However, the risk is in women with several years of hormone exposure rather than a temporary rise in estrogen during a 2-3 week IVF period.
Research found no evidence of increased breast cancer risk in women 10-20 years after IVF.
Another study focused on women who are already at a higher risk of breast cancer due to BRCA1 or BRCA2 mutations, found that fertility drugs during IVF didn’t raise the cancer risk.
The most important consideration here is fertility-related and IVF-related cancer risks. Let’s say research finds that women undergoing IVF had a slightly higher risk of breast cancer. It may seem natural to assume that IVF caused cancer.
In reality, women undergoing IVF might already have medical conditions that made them more likely to develop cancer compared to women with no such issues.
For example, women with a family history of breast cancer are already at risk. The same goes for women with BRCA1 or BRCA2 gene mutations, as well as those with a medical history of breast cancer or other abnormalities.
Increased breast cancer risk doesn’t automatically make IVF unsafe for you. A fertility expert will create a personalized IVF treatment plan while keeping your medical history in mind.
Key Evidence
American Society of Reproductive Medicine confirmed that IVF is not associated with increased breast cancer risk, although it’s advised to avoid clomiphene use for more than 10 years, as continuous or long-term hormonal changes can cause thyroid anomalies or changes in hormone-sensitive tissues, which might slightly raise your risk.
A Nordic Cohort Study monitored women who have undergone IVF for years and found no evidence of increased breast cancer risk. Many other studies, such as The Omega Study (Netherlands), The Danish National Registry Study, and The French E3N Cohort support the same findings.
Does IVF Increase the Risk of Ovarian Cancer?
Ovarian cancer, particularly, has received attention from researchers, as IVF stimulates your ovaries. Instead of a single dominant follicle, ovarian induction triggers multiple follicular growths. Experts wonder whether repeated stimulation can affect the ovarian tissues and cells from which ovarian cancer develops.
Key Evidence
Evidence for IVF-related ovarian cancer risk is comparatively more complicated than breast cancer. American Society for Reproductive Medicine states that the risk of developing ovarian cancer is slightly higher in women who’ve undergone IVF, but the study hasn’t clearly determined whether the risk is due to underlying fertility issues, such as endometriosis, or fertility drugs.
The evidence, however, is weak-to-moderate and stronger clinical research is still needed to determine the exact association between IVF and ovarian cancer. From recent findings, it’s safe to say that IVF itself isn’t the cause of ovarian cancer.
IVF and Endometrial (Uterine) Cancer Risk
Endometrial cancer develops in your uterine lining, which sheds during periods. Endometrial hyperplasia, i.e., overgrowth or excessive thickening of the uterine lining, is one of the major risk factors for endometrial cancer.
PCOS and other hormonal conditions can expose the endometrium to too much estrogen without enough progesterone to balance its effect. As a result, the uterine lining keeps thickening without shedding, increasing the risk of endometrial cancer.
What Research Says About IVF and Endometrial Cancer
Current findings do not prove any association between fertility treatments and endometrial cancer risk. The drugs used to stimulate your ovaries and the progesterone supplements may not influence your risk of developing endometrial cancer. However, earlier studies did show differences in the cancer risk in women undergoing fertility treatments and the general population.
The increased risk, however, was found to be more likely because of the underlying risk factors in women who needed IVF and other fertility procedures rather than the treatment itself. For example, Polycystic Ovarian Syndrome (PCOS) can increase endometrial cancer risk if not treated early. So, compared with the general population, women with PCOS might be at a higher risk of endometrial cancer, irrespective of whether they seek fertility treatments or not.
IVF and Cervical Cancer
In most cases, the primary cause of cervical cancer is exposure to the Human Papillomavirus (HPV), especially types 16 and 18.
Interestingly, research has found that women undergoing fertility treatments have a comparatively lower risk of invasive cervical cancer compared to the general population, as fertility treatments involve frequent screenings.
Pap tests and HPV screenings are important for all women to detect changes in cervical cells before they turn into invasive cervical cancer.
IVF and Thyroid Cancer
Research regarding thyroid cancer risk in women undergoing IVF is more complex. There’s been mixed evidence, with some reports, such as the American Society for Reproductive Medicine, stating a slightly higher risk of thyroid cancer due to constant clomiphene use. However, the evidence was classified as weak, and there’s still no scientific proof that IVF causes thyroid cancer.
Understanding Dose and Treatment Cycles
Earlier, we listed research from ASRM, which stated that persistent use of clomiphene (more than 10 cycles) and other fertility drugs should be avoided. But so far, there’s no strong clinical evidence that shows any specific number of IVF cycles that can be used for a cancer-risk threshold.
Even the above evidence was concluded as weak and shouldn’t be seen as a definitive answer to “can you get cancer from IVF”. Besides, using clomiphene for multiple cycles doesn’t mean you will develop cancer. The risk depends on many underlying health factors instead of the treatment cycle or the dose.
What Do Major Medical Organizations Say?
Let’s take a quick recap of what major organizations said about IVF and its cancer risk:
- American Society for Reproductive Medicine: The evidence showed no link between IVF and increased ovarian, breast, or uterine cancer risk, although it did mention a slightly higher risk of thyroid cancer because of hormonal changes; there’s uncertainty around the causes of cancer.
- European Society of Human Reproduction and Embryology: Studies published in ESHRE journals did not prove any connection between IVF and cancer. Small differences in the evidence found in sub-analyses were believed to be linked to underlying fertility issues rather than IVF.
- National Cancer Institute: Bulk evidence showed no link between IVF and endometrial or breast cancer, although evidence for ovarian cancer remains uncertain.
Factors That May Increase Cancer Risk Regardless of IVF
As mentioned earlier, many underlying fertility issues are linked to a heightened cancer risk, which have nothing to do with fertility treatments. Let’s discuss the real risks that can make women more vulnerable to certain hormone-sensitive and other cancers.
Age: Cancer occurring several years or decades after IVF treatment doesn’t mean that fertility treatment causes it. In fact, age itself is the major factor influencing the cancer risk of a woman’s reproductive organs.
Family History: Family history is another crucial factor. If you have had your sister, mother, or other blood relatives diagnosed with breast, ovarian, thyroid, or other cancers, you may also be at a slightly higher risk than other women.
BRCA Gene Mutations: Inherited mutations in the BRCA1 or BRCA2 genes can significantly increase the risk of breast and ovarian cancer.
Obesity: Obesity can affect hormonal balance, increasing the risk of breast, ovarian, uterine, and colorectal cancer. Increased body fat, increased inflammation, and elevated insulin can all encourage abnormal cell growth over time.
Smoking: Smoking not only affects fertility, but the toxic tobacco elements can raise a woman’s risk of different types of cancers, including cancers of the reproductive organs.
Endometriosis and PCOS: Endometriosis and PCOS can cause hormonal imbalance, i.e., increased estrogen levels, which is another risk factor for ovarian, endometrial, and uterine cancer.
What Women Should Discuss With Their Fertility Specialist
If you have cancer-related concerns or a medical or family history of cancer, share it with a fertility specialist. The type and grade of cancer you have had or that runs in your family might influence the fertility medicines you can safely take. Your fertility doctor may also recommend thorough screening if you have gene mutations or a family history of cancer.
It’s also important that you understand different treatment approaches for fertility instead of taking the IVF route immediately. Many fertility experts consider your screening reports, pregnancy history, age, health, and other factors to determine the most appropriate fertility treatment for you.
Benefits of IVF Compared to Potential Risks
When other treatments have failed or are unlikely to help couples achieve pregnancy, IVF might be their only hope. In recent years, technology has advanced, and each step in IVF is conducted and monitored carefully.
Besides, patients get a personalized stimulation protocol, where the specialist monitors their ovarian response through blood tests and ultrasound scans regularly. Modern fertility treatments focus on achieving a balanced ovarian response, instead of just collecting a large number of eggs and exposing your ovaries to large doses of medication.
FAQs
Can IVF hormones trigger cancer cells?
No, there’s no scientific evidence that suggests that hormones administered during IVF cycles can trigger cancer cell growth.
Can IVF cause ovarian cancer years later?
No strong study has proved any association between IVF and ovarian cancer that develops years later.
Should women with a family history of cancer avoid IVF?
No, a family history of cancer doesn’t make IVF unsafe for women. However, you must share your family history with your fertility doctor before starting treatment.
Does IVF increase cancer risk after age 40?
Not IVF, but advancing age is associated with increased cancer risk.
What cancer screenings should IVF patients have?
All women must get age-appropriate ovarian and breast cancer screening.
Can IVF increase the risk of breast cancer?
No, IVF is not linked to an increased risk of breast cancer.
How many women get cancer after IVF?
There’s no exact percentage showing the number of women who get cancer after IVF. The research itself is complex, with most high-authority sources linking cancers to underlying fertility conditions.
Conclusion
It’s understandable that women undergoing a major fertility treatment are concerned about their long-term health and potential risks of IVF, but research regarding IVF and its connection to cancer is reassuring so far. While some studies do show a small association between the two, the evidence isn’t strong enough to conclude that IVF poses a cancer risk. If a fertility expert advises IVF, know that it’s a safe and appropriate treatment choice for couples.
