Birth Control Gives Cancer to Women

The relationship between birth control (particularly hormonal methods like oral contraceptives) and cancer risk (including tumors) is complex and well-studied. Hormonal contraceptives, especially combined oral contraceptives (containing estrogen and progestin), influence hormone levels that can affect certain cancers. 

Research shows both increased risks for some cancers and protective effects for others. The overall balance often leans neutral or even beneficial for long-term cancer risk in many users, though individual factors like duration of use, age, and specific formulation matter.

 Increased Cancer Risks Associated with Hormonal Birth Control

Hormonal contraceptives are linked to modest increases in risk for certain cancers, particularly during current or recent use. These risks typically decline after stopping.

- Breast cancer — Current or recent use is associated with a small increased risk (around 20-30% relative increase in many studies). For example, a large analysis found a relative risk of about 1.20 for current/recent users compared to never-users. This risk rises with longer duration of use and returns to baseline within about 5-10 years after stopping. Recent 2025 studies highlight variations by progestin type, with some (like desogestrel) linked to higher risks than others (like levonorgestrel). Absolute risk remains low in younger women due to the rarity of breast cancer in premenopausal ages (e.g., roughly 13 extra cases per 100,000 women per year in some cohorts).

- Cervical cancer — Longer use increases risk, partly due to hormonal effects and potential interactions with HPV (the main cause). Risk may rise by about 10% or more with extended use, though this is influenced by screening and HPV status.

- Liver cancer — Rare associations exist with long-term use (e.g., hepatocellular carcinoma in some older data), but recent reviews suggest limited or no strong link in modern formulations.

 Protective Effects Against Certain Cancers

Hormonal birth control often reduces risk for several cancers, with benefits persisting long after discontinuation.

- Ovarian cancer — Use reduces risk by about 30-50%, with greater protection from longer duration. This effect lasts for many years post-use.

- Endometrial cancer — Similar strong protection (around 30-50% reduction), especially with prolonged use, persisting decades after stopping.

- Colorectal cancer — Evidence shows a modest reduction (around 15-20% lower risk in meta-analyses), though not all studies agree on duration effects.

Overall lifetime cancer balance in past users is often neutral, with increased risks for breast and cervical cancers offset by reductions in ovarian, endometrial, and colorectal cancers.

 Key Considerations

- Progestin-only methods (e.g., mini-pill, implants, IUDs like Mirena, injections) show similar patterns to combined pills for breast cancer risk in recent data — a small increase during/recent use — but may offer comparable protective effects for gynecological cancers.

- Risks are generally small in absolute terms, especially for younger users, and must be weighed against benefits like pregnancy prevention (which carries its own risks) and non-cancer advantages (e.g., reduced ovarian cysts, lighter periods).

- The International Agency for Research on Cancer (IARC) classifies combined estrogen-progestogen contraceptives as Group 1 carcinogens (carcinogenic to humans) based on evidence for breast, cervical, and liver cancers, but also notes protective effects.

Sources:

- National Cancer Institute (NCI): Oral Contraceptives and Cancer Risk (updated overview of observational studies showing increased breast/cervical risks and decreased ovarian/endometrial/colorectal risks).

- American Cancer Society: Birth Control & Cancer overview (2025 update on methods raising/lowering risks).

- Collaborative Group analyses and meta-analyses (e.g., on breast cancer relative risks ~1.20 for recent use).

- Recent cohort studies (e.g., Swedish 2025 data on formulation-specific breast cancer risks; UK nested case-control and meta-analysis on progestogen-only methods).

- IARC Monographs on combined hormonal contraceptives (Group 1 classification with balanced evidence).

Plastics and Cancer Risk: A Disturbing New Study on Black Plastic Products

Plastics and Cancer Risk: A Disturbing New Study on Black Plastic Products

Plastics are everywhere—our kitchens, offices, and even our bodies. But a recent study has raised serious concerns about their safety, particularly when it comes to cancer risk. On October 1, 2024, researchers from Toxic-Free Future and Vrije Universiteit Amsterdam published a study in Chemosphere revealing that black plastic items—like kitchen utensils, food containers, and toys—contain high levels of cancer-causing chemicals. This blog post dives into the study’s findings, explores the broader context of plastics and cancer, and offers practical steps to reduce exposure.

The Study: Toxic Chemicals in Everyday Black Plastics

The researchers tested 203 black plastic consumer products commonly found in U.S. households, focusing on food-contact items like sushi trays and spatulas, as well as toys and accessories. They found toxic brominated flame retardants (BFRs) in 85% of the products, with concentrations reaching up to 22,800 mg per kilogram— alarmingly high levels. BFRs are chemicals added to plastics to prevent fires, but they’ve been linked to cancer, endocrine disruption, and reproductive issues. The study also detected deca-BDE, a banned BFR, at levels 5 to 1,200 times higher than the European Union’s limit of 10 ppm, in items like a sushi tray and a beaded necklace.

Megan Liu, a co-author from Toxic-Free Future, emphasized the unintended consequences of these chemicals: “Companies continue to use toxic flame retardants in plastic electronics, and that’s resulting in unexpected and unnecessary toxic exposures.” The study suggests that recycling practices may be to blame, as BFRs from old electronics are ending up in recycled black plastics used for everyday items. This means that even seemingly harmless products—like the spatula you use to flip pancakes—could be leaching cancer-causing chemicals into your food.

The Bigger Picture: Plastics and Cancer Risk

This study isn’t an isolated warning. A growing body of research links plastics to cancer across their lifecycle—from production to disposal. A 2023 report by the Boston College Global Observatory on Planetary Health found that workers in plastic production and recycling face increased risks of leukemia, lymphoma, lung cancer, and breast cancer due to exposure to toxic chemicals. Communities near plastic manufacturing sites also show higher rates of childhood leukemia and lung cancer. Meanwhile, a December 2024 study by the Silent Spring Institute identified 414 chemicals in plastics—such as PFAS, phthalates, and aromatic amines—that are linked to breast cancer, noting that women under 50 are twice as likely to be diagnosed with cancer, with plastics exposure as a potential factor.

Microplastics, tiny plastic particles smaller than 5 mm, are another concern. They’ve been found in human blood, breast milk, and even the placenta, raising fears about their role in cancer development. A 2023 study in PMC suggested that microplastics might contribute to the rising rates of early-onset colorectal cancer in people under 50 by disrupting the gut’s protective mucus layer, leading to inflammation and DNA damage. Additionally, a 2024 study in ScienceDirect highlighted microplastics’ potential to promote cancers in the lungs, breasts, and prostate through oxidative stress and chronic inflammation.

But not all experts agree on the severity of the risk. A 2021 report from Cancer Research UK stated that there’s no reliable evidence that food and drinks stored in plastic containers cause cancer, arguing that the levels of chemical leaching are too low to be harmful. This perspective, however, clashes with animal studies showing that chemicals like BPA and phthalates—common in plastics—can mimic hormones and increase cancer risk. The establishment narrative often downplays these risks, possibly due to the plastics industry’s economic influence, but the mounting evidence suggests we should be more cautious.

A Critical Look: What’s Missing?

The Chemosphere study is compelling, but it has limitations. It focused solely on black plastics, leaving uncertainty about other colors, which may also contain BFRs or other harmful chemicals. It also didn’t explore how much of these chemicals actually leach into food or the body under real-world conditions—an area where more research is needed. Additionally, while BFRs are linked to cancer in animal studies, direct causation in humans remains unproven, a gap that skeptics often highlight.

Posts on X reflect public concern, with some users citing studies linking plastics to breast cancer and others warning about microplastics in drinking water. However, these sentiments are inconclusive without further evidence. The plastics industry might argue that BFRs are necessary for safety, but the health risks they pose—especially in food-contact items—suggest that safer alternatives should be prioritized.

What Can You Do? Practical Steps to Reduce Exposure

While the science continues to evolve, here are some steps to minimize your exposure to potentially harmful plastics:

• Avoid Black Plastic Food Items: Opt for glass, stainless steel, or wooden kitchenware instead of black plastic utensils or containers.
• Don’t Heat Food in Plastics: Heat can increase chemical leaching, so use microwave-safe glass or ceramic dishes.
• Choose BPA- and PFAS-Free Products: Check labels for products free of these chemicals, though be wary of replacements like BPS, which may also be harmful.
• Reduce Overall Plastic Use: Use reusable metal or glass water bottles and avoid single-use plastics.
• Advocate for Change: Support policies like the Global Plastics Treaty, set to be negotiated in November 2024, which aims to reduce toxic additives in plastics.

Looking Ahead: The Need for More Research and Action

The Chemosphere study is a wake-up call about the hidden dangers in everyday plastics. While it doesn’t prove that black plastics directly cause cancer, it highlights a troubling link that demands further investigation. The plastics industry has a vested interest in maintaining the status quo, but the health risks—especially for vulnerable groups like children and pregnant women—cannot be ignored. Governments need to strengthen regulations, and consumers should push for transparency about the chemicals in the products we use daily.

As plastic production continues to rise—potentially tripling by 2060, according to some estimates—the stakes are higher than ever. We need more independent research to understand the long-term effects of plastic exposure, and we need it now. Until then, reducing our reliance on plastics isn’t just good for the planet—it might be crucial for our health.

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Sources

• Chemosphere, October 1, 2024, study by Toxic-Free Future and Vrije Universiteit Amsterdam.
• Boston College Global Observatory on Planetary Health, 2023, published in Annals of Global Health.
• Silent Spring Institute, December 6, 2024, published in The Guardian.
• PMC, 2023, study on microplastics and early-onset colorectal cancer.
• ScienceDirect, 2024, review on microplastics and cancer risk.
• Cancer Research UK, 2021, statement on plastics and cancer risk.