NORPLANT and the levonorgestrel IUD in Chinese family planning programmes.

NORPLANT was introduced into the Chinese family planning programmes in 1984 by the Population Council. After a pilot study of 1200 cases in four centres in China, the study was expanded to 12 centres with 10,718 cases of NORPLANT and 1208 cases of NORPLANT-2 followed up for more than 6 years. The 5 years net cumulative pregnancy rates were 0.5-1.2 and the net cumulative continuation rates were around 65-72 per 100 users. There were significant differences in pregnancy rates between different groups of body weight and age, i.e. the pregnancy rates were higher in groups with body weight over 70 kg and those aged below 25 years. The age, body weight and dependence on contraceptive effectiveness of NORPLANT should be taken into account in the selection of users. Nationwide large-scale studies in provincial and country rural areas and postmarketing surveillance are being carried out. Changes in ovarian function and endometrium have been studied. Levonorgestrel IUD (LNg-IUD) was introduced into China in 1985. Comparative clinical studies on NORPLANT and LNg-IUD, pharmacokinetic and pharmacodynamic studies and endometrial studies of LNg-IUD were performed. The higher percentage (55.1%) of ovarian suppression in Chinese users of LNg-IUD may be attributed to ethnic differences among Caucasian women in their susceptibility to steroid hormones. Results showed favourable acceptance of both devices among Chinese women. The studies promoted the incorporation of new long-acting contraceptive methods into the Chinese family planning programmes.