The Most Significant Risks of Zoely
Zoely is a combined oral contraceptive (COC) that contains nomegestrol acetate and estradiol. While designed to be an effective birth control method, it is important for users to be aware of the associated risks, some of which can be serious.
Increased Risk of Blood Clots (Thromboembolism)
One of the most significant risks of combined hormonal contraceptives is the increased chance of developing a blood clot, known as a thromboembolism.
- Venous Thromboembolism (VTE): This refers to blood clots in the veins, most commonly in the legs (deep vein thrombosis or DVT) or lungs (pulmonary embolism). While the absolute risk for any individual woman is low, it is higher for those using Zoely compared to those not on combined pills. The risk is particularly elevated during the first year of use and when restarting the pill after a break of four weeks or more. The danger increases with factors like smoking, obesity (BMI over 30 kg/m$^2$), increasing age (over 35), a history of blood clots in the immediate family, and long periods of immobility.
- Arterial Thromboembolism (ATE): This involves blood clots in the arteries, which can lead to a heart attack or stroke. The risk is higher for women who smoke, are overweight, have high blood pressure, or a family history of heart attack or stroke. Women who experience migraines, especially those with aura, are at a higher risk.
Cancer Risks Associated with Hormonal Contraceptives
Combined oral contraceptives have been linked to a slightly increased risk of certain types of cancer, though the exact relationship and magnitude of risk are complex.
- Breast Cancer: Studies have shown a small increase in breast cancer risk among women currently using or recently having used hormonal contraception. This risk appears to decrease over time after discontinuing use and returns to normal about 10 years after stopping.
- Cervical Cancer: Prolonged use of combined oral contraceptives (5 years or more) is associated with an increased risk of cervical cancer. This may be influenced by other factors such as sexual behavior and HPV infection, but the risk declines over time after discontinuation.
- Liver Tumors: In rare cases, both benign and malignant liver tumors have been reported in users of hormonal contraceptives. These can be serious and potentially life-threatening.
- Meningiomas: A generally benign tumor of the tissue layer covering the brain, meningioma has been linked to nomegestrol acetate, one of the active ingredients in Zoely. The risk is associated with high doses and long-term use. Your doctor may stop your treatment if this diagnosis is made.
Mental Health Effects
Changes in mood are among the most common side effects reported by users of hormonal contraceptives.
- Depression and Anxiety: Many women, particularly those with a history of mood disorders, report experiencing changes in mood, increased anxiety, and depression while on combined pills like Zoely. Some have reported severe depression and suicidal thoughts. For some users, symptoms intensify before their period.
- Other Mood Changes: Users have also reported increased irritability, mood swings, and a decreased interest in sex.
Other Common Side Effects
Aside from the serious risks, Zoely can cause several other common side effects:
- Acne
- Changes in menstrual bleeding (irregular, lighter, or absent periods)
- Headaches and migraines
- Nausea and vomiting
- Weight changes (gain or loss)
- Breast enlargement or tenderness
- Fluid retention
- Loss of libido
Contraindications for Zoely Use
Zoely should not be taken by women with certain pre-existing conditions that significantly increase the risk of serious complications. These include:
- History of blood clots (VTE or ATE) in the legs, lungs, heart, or brain.
- Severe liver disease or liver tumors.
- Known or suspected sex-steroid influenced malignancies, such as breast cancer.
- Undiagnosed vaginal bleeding.
- History of migraines with focal neurological symptoms.
- Uncontrolled hypertension or severe dyslipoproteinaemia.
Comparing Zoely Risks with Other COCs
While all combined oral contraceptives carry similar general risks, there can be differences in the specifics of their hormonal makeup and how they are studied. Zoely is unique as it contains estradiol, which is identical to the estrogen produced naturally by the body, rather than the synthetic ethinyl estradiol found in many other COCs.
| Feature | Zoely (Nomegestrol Acetate / Estradiol) | Traditional COC (e.g., Levonorgestrel / Ethinyl Estradiol) | Note |
|---|---|---|---|
| Estrogen Type | Natural estradiol | Synthetic ethinyl estradiol | Natural estradiol may offer a slightly different metabolic profile. |
| VTE Risk | Similar to low-dose levonorgestrel-containing COCs | Variable, depending on progestin type; some have lower risk than others. | Risk is elevated compared to non-users for both. |
| Bleeding Pattern | Shorter and lighter periods; more instances of no withdrawal bleeding. | Typically regular withdrawal bleeding. | Bleeding patterns vary per person and pill type. |
| Acne/Weight | Acne and weight gain reported frequently in some studies. | Can cause or improve acne and affect weight, depending on formulation. | Individual response varies; consult a doctor. |
Conclusion
For many women, the benefits of Zoely as an effective contraceptive and regulator of menstrual cycles outweigh the potential risks. However, the decision to use Zoely, or any hormonal contraceptive, must be a careful and informed one made in consultation with a healthcare provider. Serious risks, such as blood clots and certain cancers, while rare, are a significant consideration, as are the more common side effects including mood changes and menstrual irregularities. Individuals with specific risk factors like a history of thromboembolism, severe liver disease, or certain types of cancer are advised to avoid Zoely. Continuous monitoring of potential side effects and health changes is recommended throughout treatment.
If you are considering starting Zoely or have concerns about your current use, it is best to discuss your individual health profile and risk factors with a medical professional. For detailed prescribing information, you can consult sources such as the European Medicines Agency (EMA).
