6 New hormonal methods of contraception

Abstract

Three types of new contraceptive delivery system have been discussed in this chapter. Each have novel methods of delivery and may be acceptable to certain groups of women. It is clear that subdermal contraceptive implants are extremely useful as a long-term method of contraception, and provided insertion occurs correctly, removal will then be easy. The second-generation implants using a single rod, compared with the first-generation ones using six capsules, would appear to offer advantages both to the patient and in relation to the training of medical and paramedical personnel who have to fit the subdermal implant. The main disadvantage is the incidence of irregular bleeding, which, by and large, can be overcome by pre-insertion counselling and by time. The second method of delivery, vaginal rings, offers high patient acceptability, but a usable ring for contraception has as yet to be developed. Two approaches appear to be the use of a continuous progestogen-only ring, or a combined ring releasing oestrogen and progestogen with a 21-day-in, 7-day-out cycle of use. Ongoing studies will indicate whether vaginal lesions are significant or related to the flexibility of the ring. If these studies prove satisfactory, further development of the vaginal rings, both as an alternative method for interval use or as a specific postpartum form of contraception using progesterone-releasing rings, will be developed. Significant developments in the use of a combined monthly injectable have led to the release of two preparations, Cyclofem and Mesigyna, which are now available in many countries. This combined approach offers a significant reduction in amenorrhoea rates and unacceptable bleeding, the majority of women having acceptable menstrual patterns even during the first 3 months of use. All three methods have low and acceptable rates of pregnancy, the lowest being seen with the subdermal implants and with combined monthly injectables. Due to the length of action of subdermal implants, these may find a niche for women wishing to use a long-acting method and not wishing to be sterilized. They also provide a useful method where medical intervention is not available on a regular basis. Monthly injectable preparations can be given by paramedical personnel, and introductory studies have indicated that in developing and developed countries, they are highly acceptable. All three methods offer an increased choice for women and safe and effective methods of contraception.