Weight-loss jabs can stop HRT working, doctors warn

Telegraph

14 hours ago

Weight-loss drugs could stop hormone replacement therapy from working and increase the associated risks, guidance has warned.
The British Menopause Society has told doctors to closely monitor any women who are on hormone replacement therapy (HRT) for the menopause and are also taking a weight-loss jab.
The injections, such as Mounjaro and Wegovy, also sold as Ozempic for diabetes, have revolutionised obesity treatment and are increasingly taken by people who are not obese but looking to lose a few pounds.
But the drug's ability to delay the transit of food through the gut can slow the absorption of pills taken orally. It is one theory behind the so-called ' Ozempic baby boom '.
Earlier this week, the medicines regulator issued a warning about the impact of weight-loss drugs on contraception after receiving more than 40 reports relating to pregnancies from women on the jabs.
The Medicines and Healthcare products Regulatory Agency said women should 'not rely on oral contraception' and warned them not to use the injections if pregnant or trying to get pregnant because of a lack of safety evidence.
Guidance has now suggested women taking HRT orally may also be at risk.
There were 2.6 million women taking HRT in 2023-24 in England to help with symptoms of the menopause, which can include hot flushes, night sweats, difficulty sleeping, mood changes, and muscle aches. It typically onsets between age 45 and 55 and can last for a number of years.
The most common form of HRT is a progesterone pill alongside a skin patch or gel to deliver oestrogen, although some women will be on a combined pill.
The progesterone is important to balance out the effects of oestrogen, which on its own stimulates the growth of the womb lining, and can cause ' abnormal cells and cancer ' to grow.
The loss of the protective effect of progesterone on the womb was the primary concern for the British Menopause Society, which recommended doctors move women to an intrauterine device, such as a Mirena coil, or increase the dose of progesterone.
Prof Annice Mukherjee, a consultant endocrinologist and member of the society's medical advisory council, who led on the guidance, said an imbalance in the hormones, particularly among women with obesity, would put them 'at increased risk of womb cancer '.
'Oestrogen is almost always given through the skin for HRT in women living with obesity, but progesterone is frequently given as a tablet, and that formulation is thought to be the safest route for women who have complicated health issues,' she said.
'If we then start one of these injectable weight-loss drugs, then you're preferentially stopping absorption of the progestogen that's coming in orally, but you're allowing plenty of the oestrogen through the skin.
'The rules are very clear that if you give a very high dose of oestrogen and you don't give enough progesterone, however that happens, you're putting that woman at risk of womb cancer,' she said.
Prof Mukherjee said there was currently a 'culture of putting women on very high doses of oestrogen', which can make the womb lining thicken.
'It's like having a lawn in a woman's womb. Oestrogen makes the lawn grow. Progestogen cuts the lawn. But if it's not being cut, it grows thicker, and then you can get abnormal cells and cancer.'
But she also stressed that the biggest risk factor for womb cancer was obesity and so on the whole the weight-loss injections were a positive tool to reduce weight and cancer risk.
'These drugs reduce the risk of cancer,' she said. 'But if they are prescribed to a woman who's on oestrogen through the skin, and she might already have womb thickening because she's living with obesity, and she's not absorbing the progesterone because she's been put on a weight-loss injection, she's potentially getting loads of oestrogen on top of her thickened womb lining, and that could potentially unmask cancers that are there or drive an early cancer to a more advanced stage.'
More than 1.5 million people in the UK are now taking weight-loss jabs, with demand doubling in the last six months. The overwhelming majority are accessing them privately from pharmacies at a cost of around £200 per month.
It is not known how many people are on both drugs, but the British Menopause Society has created guidelines after calls from GPs for advice to give to patients.
Dr Janet Barter, the president of the Faculty of Sexual and Reproductive Healthcare, said there was 'a small but growing body of evidence that the new diabetes and weight loss drugs, which can bring really positive improvements to people's health, can also cause vomiting and severe diarrhoea in some patients'.
'Obviously this could render any medication, such as HRT tablets or oral contraception, ineffective if there hasn't been enough time for them to be fully absorbed,' she said. 'If these side-effects are occurring, then people should discuss the matter with their doctor or specialist clinician to find the combination of drugs that's right for them.'