Norplant植入法是一种高效的避孕方法,药效可持续5年。已知其避孕机理是抑制排卵,但使用头2年80％～90％的妇女可见明显的无排卵周期,到第5年末血浆孕酮(P)水平仅有55％周期符合无排卵,其余周期P均达到排卵水平(P>3ng/ml)。认为Norplant还存在着其它避孕机理。为此,对Norplant使用者进行经前期hCG测定,并证明足以检出早期1CG存在的敏感性与对照组进行对比。治疗组为32名性生活正常,月经周期规律的已使用 The Norplant method is an effective contraceptive method that lasts for 5 years. Known contraceptive mechanism is to inhibit ovulation, but the use of the first 2 years 80% ~ 90% of women visible no ovulation cycle, by the end of 5 plasma progesterone (P) level only 55% of the cycle in line with anovulation, the rest of the cycle P reached ovulation level (P> 3ng / ml). Norplant believes there are other contraceptive mechanisms. To this end, Norplant users were pre-treated with hCG and demonstrated sufficient sensitivity to detect the presence of early 1CG as compared to controls. The treatment group was 32 normal sex life, menstrual cycle has been used