Barbosa I, Bakos O, Olsson S E, Odlind V, Johansson E D
Department of Obstetrics and Gynecology, University of Uppsala, Sweden.
Contraception. 1990 Jul;42(1):51-66. doi: 10.1016/0010-7824(90)90092-a.
Ovarian function was studied for two complete menstrual cycles in 9 regularly menstruating women and for 8 weeks in three amenorrhoeic women who had used levonorgestrel-releasing IUDs (LNG-IUD) for more than four years. Nine patients using copper IUDs (Nova-T) were studied for two complete menstrual cycles as controls. According to progesterone levels, 15/17 cycles in women using LNG-IUDs were ovulatory, whereas only 8/17 cycles showed normal follicular growth and rupture as judged by ultrasound. In ovulatory cycles, the peak progesterone levels were lower than in the controls. The preovulatory estradiol and LH peak levels were also lower than in control subjects. SHBG levels were lower in LNG-IUD users than in copper IUD users. It is concluded that, although the dose of levonorgestrel released from the IUD is very low, it probably exerts an effect on the gonadotrophin secretion, which disturbs follicular development in many of the women studied, which in addition to the local effect on the endometrium, contributes to its high contraceptive efficacy.
对9名月经周期正常的女性进行了两个完整月经周期的卵巢功能研究，对3名使用左炔诺孕酮宫内节育器（LNG-IUD）超过四年的闭经女性进行了8周的卵巢功能研究。作为对照，对9名使用铜宫内节育器（Nova-T）的患者进行了两个完整月经周期的研究。根据孕酮水平，使用LNG-IUD的女性中15/17个周期有排卵，而通过超声判断只有8/17个周期显示正常的卵泡生长和破裂。在有排卵的周期中，孕酮峰值水平低于对照组。排卵前雌二醇和促黄体生成素峰值水平也低于对照受试者。LNG-IUD使用者的性激素结合球蛋白（SHBG）水平低于铜宫内节育器使用者。得出的结论是，尽管宫内节育器释放的左炔诺孕酮剂量非常低，但它可能对促性腺激素分泌产生影响，在许多研究的女性中干扰卵泡发育，这除了对子宫内膜的局部作用外，还促成了其高避孕效果。
