A tampon-like device could help women who’ve had a miscarriage have a baby.
The invention dispenses progesterone, a hormone that plays a key role in the early stages of pregnancy.
Progesterone thickens the lining of the womb to prepare it for pregnancy and helps the embryo implant. But an estimated 400,000 women in the UK either don’t make enough progesterone or their womb doesn’t respond properly to the progesterone they make.
Known as luteal phase insufficiency, it can make it harder to get pregnant and is suspected to be a leading cause of miscarriage.
Currently, it is treated with progesterone pessaries, inserted into the vagina twice a day.
The PRISM trial of 4,000 women, published in the New England Journal of Medicine in 2019, found that 400mg progesterone pessaries twice a day resulted in a small reduction in miscarriage for women who had experienced one or two previous miscarriages. And a big reduction for those who’d had three or more previous miscarriages (with a live birth rate of 72 per cent compared with 57 per cent in the placebo group).
However, while effective, the pessaries are problematic ‘and many women hate using them’, says Siobhan Quenby, a professor of obstetrics at the University of Warwick. For example, they cause a discharge which can be unpleasant and a source of worry, she explains.
Women who’ve had a miscarriage could be able to get pregnant with the help of a new tampon-like device
Callavid is the size and shape of a conventional tampon, and is designed to stay inside the body until all of the progesterone is absorbed
‘This causes anxiety because just before you miscarry or have a preterm birth there is often some discharge – and if you’ve lost pregnancies, you’re terrified it will happen again in the next pregnancy.
‘So giving pessaries that cause vaginal discharge is not good for women’s mental health.’
And with up to 10ml – two teaspoons – of fluid being leaked per pessary, women also worry that they aren’t receiving the full dose of progesterone. (It isn’t clear if the discharge contains the hormone.)
‘To minimise leaking, women get up an hour early to lie down after administering their first pessary of the day (the second can be done before bed), so it causes massive problems in their daily life,’ says Professor Quenby.
There is also a risk that the pessaries aren’t positioned properly, which could reduce absorption or could even lead to them slipping out.
Some women who have had at least one miscarriage are given progesterone injections into their thighs or abdomen – typically in private clinics rather than within the NHS – but these can be painful and carry an infection risk.
The hope is the new device – which is the size and shape of a conventional tampon, and is designed to stay inside the body until all of the progesterone is absorbed – will be more effective, simpler to use and cause less anxiety than the pessaries.
Called Callavid, it is now being tested on women in a trial at University Hospitals Coventry and Warwickshire NHS Trust, led by Professor Quenby and funded by the National Institute for Health and Care Research.
Professor Siobhan Quenby is leading a trial where the new device will be tested on 20 women at University Hospitals Coventry and Warwickshire NHS Trust
In the trial, 20 women who have luteal phase insufficiency, aren’t pregnant and have had at least one miscarriage, will use the tampon-like device for one week and then a standard pessary during the same days of their menstrual cycle another month. Both administer 400mg progesterone and are used twice a day.
Women will be given tests to measure levels of progesterone at the start and end of each week of treatment. They’ll also answer questions about how comfortable they found the treatments and wear sanitary pads to collect any fluid that is discharged.
If the trial is successful, the Callavid device could be available by the end of next year. The new ‘tampon’ is mainly made from organic cotton. The tip is coated in a progesterone and vegetable fat mixture, which softens after insertion, releasing the hormone. The other end has a soft absorbent disc, which stays outside the body, to prevent any leaks.
The device is left in place for two hours, to allow the progesterone to be absorbed. It can then be removed, using a string (like a standard tampon) – and discarded. Women can move and go about their normal lives with it in place.
Progesterone pessaries are also used to help stop women who are bleeding in early pregnancy from miscarrying, to prevent premature births (by reducing contractions of the uterus) and to boost the odds of the embryo implanting in IVF. The manufacturer hopes Callavid will be used for these purposes, too.
Early research suggests vaginal progesterone such as that delivered with the new device can cut the risk of pre-eclampsia if given in the first trimester. This is a potentially fatal complication of pregnancy, and so it might be possible to use the device here, too.
In pre-eclampsia the placenta releases harmful proteins into the mother’s bloodstream which raises blood pressure and causes other complications – it’s thought that progesterone may prevent this happening, although the exact mechanism is not yet clear.
It could also potentially be used to deliver progesterone as part of HRT and to ferry drugs for vaginal and cervical cancers where they are needed – which could reduce side-effects.
‘Using pessaries to deliver progesterone causes a huge amount of distress for women when they slip out, if they think it hasn’t been absorbed properly or hasn’t been put in the correct position and the progesterone isn’t getting into the right place,’ says Dr Emma Kirk, a consultant gynaecologist at the Royal Free Hospital in London and vice chairwoman of the Association of Early Pregnancy Units.
‘This device would give them the reassurance that the medication is staying inside their body and doing what it should be doing – and I would hope it will work better than pessaries at stopping leakages.’
There is one clear drawback, she adds: ‘From an environmental perspective it will create a lot of waste because the devices aren’t reusable or biodegradable.
‘If it was used to prevent miscarriage, then women would need two every day for 12 weeks (equalling 168 devices).’
