Intrauterine contraception – what now and what next?

Abstract

Rising each year by around 85 million, we have started this millennium with over 6,000 million, mostly utterly destitute, human beings on a finite planet. We will never meet human needs without stabilizing human numbers.In the sexual arena, all human beings (but especially the males of the species) are very bad at using their brains and their genitalia at the same time, i.e. putting the knowledge in their head about risks of conception or of sexually transmitted infections into appropriate preventive action when sexually aroused! Therefore, a very useful criterion for choice of methods all through the various stages of reproductive life is 'forgettability'. This is a great 'plus' point for the intrauterine route, especially the levonorgestrel intrauterine system (LNG-IUS).Its main contraceptive effects are local, by endometrial suppression and changes to the cervical mucus and uterotubal fluid, which impair sperm migration. The blood levels of levonorgestrel are about one-quarter of the peak levels in users of the progestin-only pill, and so gestagenic symptoms are uncommon and ovarian function is little altered. Most women continue to ovulate and, in the remainder, sufficient estrogen for health is produced from the ovary even if they become amenorrheic, as many do; this is primarily a local end-organ effect and should be seen as a benefit. Postmenopausal estradiol levels have not been detected, even in those who have no uterine bleeding.Although usable by selected nulliparae, the LNG-IUS is a particularly good choice for the parous woman, for whom I maintain it represents the future already here, which is not recognized by many providers. It has unsurpassed efficacy; 99.5% of women have not conceived after 5 years of use. Return of fertility is rapid and appears to be complete. Combining the best features of hormonal and intrauterine contraception without most ofthe problems of either, it fundamentally 'rewrites the textbooks' about intrauterine devices. Its gynecological benefits are impressive: the LNG-IUS user can expect a dramatic reduction in amount and, after the first few months, in duration of blood loss. Dysmenorrhea is also greatly benefited, in most cases.In summary, the LNG-IUS fulfils many of the criteria for an 'ideal' contraceptive. Adverse side-effects are few and, in general, they are not in the category 'hazardous'. Regarding the inconvenience of the first weeks of light post-insertion bleeding and the early-phase low incidence ofsteroidal side-effects, forewarned is forearmed!