WOMEN’S BODIES: FUTURE HORMONAL METHODS – II
Hormone-releasing vaginal rings
Medicines are well absorbed into the blood from the vagina. There are advantages in absorbing contraceptive hormones from places other than the bowel: there isn’t the risk of reduced absorption during digestive upsets; it also reduces the load on the liver.
Hormone-releasing vaginal rings are; made of a special plastic that incorporates hormone(s); these are released into the vagina and absorbed into the blood. Two types are currently being developed.
Rings that contain progestogen
These are worn constantly in the vagina (though they may be removed for intercourse) where they release steady amounts of hormone. The present model is changed every 90 days.
Progestogen-releasing rings work in much the same way as implants, though about 50 per cent of women ovulate while wearing the rings. The rings release a lower dose than implants or injections and thus have fewer side-effects. One of their advantages is that they can be inserted without surgical procedure, and when contraception is no longer needed the ring is simply removed.
Rings that contain an oestrogen and a progestogen These are worn in the vagina for three weeks followed by a ‘week ff’, and work in exactly the same way as the combined oral contraceptive. However, because hormones are more reliably absorbed from the vagina than from the bowel and because the hormones go straight into the blood without having to pass through the liver first, lower doses can be used.
Hormone-releasing vaginal rings have been researched in many countries. They are not yet available in Australia. The combined ring is currently being mailed by FPA’s Sydney research
centre, where an intra-cervical hormone-releasing contraceptive device is also under study.
An intracervical, hormone-releasing device is being tested. It releases enough hormone locally to have an antifertility effect on cervical mucus, but not enough hormone is absorbed to disturb the menstrual pattern.
Hormone-releasing IUDs are available in some countries and are being tested in Australia. They combine the effects of the IUD with the effect of progestogen on cervical mucus and the endometrium. Progestogen-releasing IUDs reduce menstrual loss and have been used successfully to treat some types of menorrhagia. For some users, spotting between periods is an unwanted side-effect.
Vaginal Pill
The efficacy of combined and progestogen-only vaginal pills is being tested at present.
A male Pill?
Remember gossypol? This made big headlines in 1978 when it was identified as the reason for reduced fertility in parts of China where cottonseed oil was used for cooking. Over the past 15 years studies on its safety and efficacy have continued in China, but as 25 per cent of men who’ve used it have remained permanently infertile, gossypol’s looking less and less promising. There is no other male Pill on the horizon.
Male contraceptive injection
Weekly injections of the hormone testosterone switch off sperm production in the majority of men and reduce production in the remainder. Studies over the past 20 years have shown that when men have their sperm production switched off completely by this hormonal method, it works as a very effective contraceptive (at least as good as other reversible methods including the Pill, and more effective than condoms).
The hormones produce very few side-effects and, after stopping treatment, sperm counts return to normal within the expected time of three to four months. Studies of the male injection are continuing in many centres around the world, including Melbourne and Sydney.
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