Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Contraception. 2013 Apr;87(4):432-6. doi: 10.1016/j.contraception.2012.12.001. Epub 2012 Dec 10.
A single study shows that contraceptive vaginal ring (CVR) use for up to 35 days in women with a normal body mass index (BMI) maintains serum hormone levels sufficient to suppress ovulation. This study is intended to confirm those results and to evaluate prolonged CVR use up to 42 days in both normal BMI and obese women.
Twenty women with a normal BMI and 20 obese women enrolled in a prospective open label clinical study of ethinyl estradiol (EE) and etonogestrel (ENG) pharmacokinetics during six weeks of use of a single CVR. Participants underwent twice-weekly evaluations to determine serum hormone concentrations, ovarian follicle development, endometrial thickness and bleeding patterns.
Thirty-seven women completed follow-up including eighteen women with a normal BMI and nineteen obese women. EE and ENG concentrations remained in therapeutic range for all women. Follicular development and endometrial proliferation were minimal. By the sixth week, 30% of participants reported spotting or bleeding.
A single CVR used for 6 weeks demonstrates therapeutic serum levels of EE and ENG among women with normal and obese BMI. Women who forget to remove the CVR at day 21 may well have continued contraceptive protection during the next 3 weeks.
一项研究表明，对于体重指数（BMI）正常的女性，使用避孕阴道环（CVR）长达 35 天可维持足以抑制排卵的血清激素水平。本研究旨在证实这些结果，并评估 CVR 在正常 BMI 和肥胖女性中最长使用 42 天的情况。
20 名 BMI 正常的女性和 20 名肥胖女性参与了一项为期六周的单环雌二醇（EE）和依托孕烯（ENG）药代动力学的前瞻性开放标签临床研究。参与者每两周接受一次评估，以确定血清激素浓度、卵巢卵泡发育、子宫内膜厚度和出血模式。
37 名女性完成了随访，包括 18 名 BMI 正常的女性和 19 名肥胖女性。所有女性的 EE 和 ENG 浓度均保持在治疗范围内。卵泡发育和子宫内膜增殖很小。到第六周，30%的参与者报告有点滴出血或出血。
使用单环 CVR 6 周可在 BMI 正常和肥胖的女性中达到 EE 和 ENG 的治疗血清水平。忘记在第 21 天取出 CVR 的女性在接下来的 3 周内可能会继续得到避孕保护。
