Samsioe G
Department of Obstetrics and Gynecology, Lund University, Sweden.
Am J Obstet Gynecol. 1994 May;170(5 Pt 2):1523-7. doi: 10.1016/s0002-9378(94)05014-3.
Epidemiologic data support the notion that first-generation high-dose oral contraceptives (containing > 80 micrograms of estrogen) increased the incidence of thromboembolic events. The quantitative interpretation of these data is difficult because results were often confounded by life-style factors and inadequate diagnostic procedures. With the introduction of modern low-dose combination oral contraceptives, the incidence of thromboembolic events decreased markedly. Although all combined oral contraceptives induce statistically significant changes in hemostatic factors, these changes are generally within normal ranges, and their clinical significance is questionable. Overall, increased activity in hemostatic mechanisms appears to remain in balance. Progestin-only formulations seem to affect hemostatic parameters to a much lesser degree, and their use has not led to an increased risk of thrombosis. Interindividual variations in pharmacokinetics and pharmacodynamics of contraceptive steroids are great and could tentatively explain why certain persons may be at an increased risk of thrombosis. Although most studies have looked at steady-state conditions during contraceptive steroid intake, it would seem prudent to investigate further the hemostatic system during a non-steady-state condition, such as that occurring during the first few days of the pill-free interval.
流行病学数据支持这样一种观点，即第一代高剂量口服避孕药（含雌激素超过80微克）会增加血栓栓塞事件的发生率。对这些数据进行定量解读很困难，因为结果常常受到生活方式因素和诊断程序不完善的干扰。随着现代低剂量复方口服避孕药的问世，血栓栓塞事件的发生率显著下降。尽管所有复方口服避孕药都会引起止血因子在统计学上的显著变化，但这些变化通常在正常范围内，其临床意义存疑。总体而言，止血机制活性的增强似乎仍保持平衡。仅含孕激素的制剂对止血参数的影响要小得多，使用这类制剂并未导致血栓形成风险增加。避孕药类固醇的药代动力学和药效学存在很大的个体差异，这或许可以初步解释为什么某些人血栓形成风险可能会增加。尽管大多数研究关注的是服用避孕药类固醇期间的稳态情况，但进一步研究非稳态情况下（如停药间隔最初几天出现的情况）的止血系统似乎是审慎之举。
