Clinical results have shown that a new, locally acting female contraceptive, effective for at least five years, combines the best attributes of the Pill and the intrauterine device.
Prof John Guillebaud, of University College, London, a leading British gynaecologist, said he called it "the forgettable contraceptive" because of its fit-and-forget benefit. But it should not, he added, be considered an intrauterine device.
In Dublin to address a medical conference, Prof Guillebaud said clinical results had shown it was ideal for the "thirty something" woman, especially if she had had a child.
The T-shaped device with its small cylinder releases low doses of the hormone, levonorgestrel, daily. It was "a system which had rewritten the textbooks about intrauterine contraception".
Some 70 GPs in Ireland have been using the Mirena system on a trial basis, following 30 years of research and development. Its success will lead to a GP training programme being extended significantly during 1999.
According to Prof Guille baud, studies show it is even more effective than sterilisation, with failure rates as low as 0.1 per 100 women years, compared to 0.4 for sterilisation and up to 10 for the condom in typical use. In addition, fertility is easily restored after it is removed.
Delivering the hormone in a localised way meant only extremely low levels got into the blood stream, significantly lower than many other forms of the Pill. Side-effects, such as breast tenderness, headache or acne, were less likely.
The list of potential side-effects was small compared to the oestrogen pill. Where they did occur, they usually disappeared after a few months, he said.
Its non-contraceptive use was to reduce heavy periods, which in turn helped avoid the need for hysterectomy or other surgical procedures.
The hormone acts directly on the inner wall of the uterus. It thickens mucus which prevents sperm reaching the egg but it also reduces the likelihood of implantation.
The system costs £121 in Ireland, not including installation, and it is available under the General Medical Scheme. Prof Guillebaud said, however, as someone born in Africa he was acutely aware of the need to make it available to the Third World at a much cheaper cost.
Dr Mary O'Flynn, a Limerick GP, said hormone tests had shown that, unlike the intrauterine coil, the system was not an abortifacient. Her patients using it associated it with freedom because of the lack of oestrogen-like side-effects. Yet it was so easily reversible when they wanted to have a baby.
