British Menopause Society sounds alarm as ‘skinny jabs’ may cause hormone imbalance in millions of women taking HRT – leaving them at ‘increased risk of womb cancer’
Weight loss injections hailed as miracle drugs could be putting millions of women at risk by preventing crucial medications from working properly – and potentially increasing their cancer risk, experts have warned.
The British Menopause Society has raised urgent concerns that popular slimming jabs including Wegovy, Mounjaro and diabetes drug Ozempic could cause dangerous hormone imbalances in women taking hormone replacement therapy (HRT), particularly those with obesity.
In a stark warning that will alarm the estimated two million British women on HRT, the society said the weight loss drugs could leave patients “at increased risk of womb cancer” by interfering with how their bodies absorb vital hormones.
Pills Not Working Properly
The alarm follows revelations that the Medicines and Healthcare products Regulatory Agency (MHRA) has already warned women that weight loss medications could make the contraceptive pill less effective – with 40 reports of pregnancies among users of the jabs.
The concern centers on how these drugs – known as GLP-1 receptor agonists – work by slowing down the passage of food through the gut and delaying stomach emptying. This same mechanism that helps people lose weight could also delay the absorption of pills taken orally, including both contraceptives and HRT.
The British Menopause Society (BMS) has now told doctors to closely monitor menopausal women on HRT who are also using weight-loss jabs, amid fears that improper hormone absorption could have serious health consequences.
Cancer Risk Warning
For women taking HRT in pill form, the implications could be severe. HRT works by carefully balancing hormones to manage menopause symptoms – but if the medication isn’t absorbed properly, it could lead to dangerous imbalances.
The BMS specifically warned that women with obesity taking HRT could be left “at increased risk of womb cancer” if their hormone therapy is disrupted by weight loss drugs.
This is because unopposed estrogen – when estrogen is not properly balanced with progesterone – is known to increase the risk of endometrial (womb) cancer. If weight loss drugs prevent proper absorption of HRT, particularly the progesterone component, it could leave women exposed to this increased cancer risk.
Contraceptive Chaos
The warnings come after the MHRA received multiple reports of women becoming pregnant while using weight loss drugs despite being on the pill.
The agency received 26 pregnancy-related reports concerning Mounjaro (tirzepatide), eight reports linked to semaglutide-based drugs (Ozempic and Wegovy), and nine reports for Saxenda, which contains liraglutide.
Unlike Ozempic and Wegovy, Mounjaro specifically carries a warning on its label that oral contraceptives may be less effective. The drug’s prescribing information advises women to use barrier contraception like condoms for four weeks after starting the medication and for four weeks after each dose increase.
How The Drugs Interfere
Dr. Phillip Kadaj, an endocrinologist and medical expert, explained: “These drugs slow how fast the stomach empties anything that’s ingested. This creates some theoretical concerns in regard to absorption of medication, including birth control pills.
“If the hormones in birth control pills aren’t being fully absorbed because of the delayed emptying from semaglutide, there’s a chance that the pill may not be quite as effective.”
The same principle applies to HRT – if the hormones aren’t being properly absorbed due to delayed stomach emptying, women may not be getting the full protective benefits of their therapy.
‘Victorian Attitudes’ But Real Risks
The warnings highlight a complex dilemma for the millions of women who could benefit from both treatments. Weight loss drugs have been hailed as revolutionary for helping people shed pounds, while HRT remains the most effective treatment for menopause symptoms.
Research has shown that postmenopausal women on HRT who take semaglutide actually lose MORE weight than those not on hormone therapy – suggesting a potential benefit to combining the treatments. However, this must be balanced against the risks of improper hormone absorption.
What Women Should Do
Experts are urging women not to panic but to take precautions:
For Contraception:
- Women on Mounjaro should use backup contraception (like condoms) for 4 weeks after starting and after each dose increase
- Consider switching to non-oral methods like the patch, ring, implant or IUD
- Be aware that vomiting or diarrhea (common side effects) can also affect pill effectiveness
For HRT:
- Discuss with your doctor about switching from oral HRT to patches or gels, which bypass the digestive system
- Ensure close monitoring of hormone levels and symptoms
- Be vigilant for any breakthrough bleeding or return of menopause symptoms
Doctor’s Stark Warning
Dr. Alison Cave, the MHRA’s chief safety officer, urged: “Patients should not misuse these medications for weight loss. They are licensed for specific medical conditions and not for cosmetic purposes.”
She recommended that patients “read the provided patient information leaflets and consult healthcare professionals before using these powerful treatments.”
The Growing Crisis
With obesity affecting 28% of adults in England and menopause affecting all women, the overlap between those who could benefit from both treatments is substantial.
The NHS has seen unprecedented demand for weight loss drugs, with private clinics also reporting soaring sales. Meanwhile, HRT prescriptions have more than doubled in recent years as awareness of menopause treatment has improved.
But the new warnings suggest that combining these treatments requires careful medical supervision and may not be as straightforward as many had hoped.
Expert Advice
Dr. Channa Jayasena, a consultant in reproductive endocrinology, noted: “GLP-1 medications like Ozempic and Wegovy are effective in aiding weight loss but could increase fertility in women with obesity by enhancing fertility. However, these drugs may also interfere with the absorption of oral contraceptives, potentially increasing the risk of unintended pregnancies.”
The Faculty of Sexual and Reproductive Healthcare has issued updated guidance, stating that while there’s no direct evidence that Ozempic and Wegovy affect birth control, women should be aware of the theoretical risk and consider taking precautions.
The Bottom Line
As these wonder drugs continue to transform weight loss treatment, women must be aware of the potential interactions with other vital medications.
The message is clear: if you’re taking weight loss injections alongside the pill or HRT, speak to your doctor about whether you need to adjust your treatment plan.
With proper medical guidance, it may be possible to benefit from both treatments safely – but the days of assuming all medications work perfectly together are over.
For the millions of women navigating menopause, weight concerns, and contraception, these new warnings add another layer of complexity to an already challenging time.
But with awareness and appropriate precautions, the benefits of these treatments can still outweigh the risks – as long as women and their doctors work together to ensure all medications are working as intended.
