Rosenberg M J, Waugh M S, Stevens C M
Health Decisions, Inc., Chapel Hill, NC 27515, USA.
Am J Obstet Gynecol. 1996 Feb;174(2):628-32. doi: 10.1016/s0002-9378(96)70440-4.
Because cigarette smoking has a variety of antiestrogenic actions, we investigated the possibility that smoking may adversely affect spotting and bleeding among women using oral contraceptives.
Three open-label, randomized clinical trials involving 16,506 cycles among 2956 oral contraceptive users were performed.
Smokers reported a consistently higher frequency of spotting or bleeding than did nonsmokers. After recency and consistency of oral contraceptive use and progestin component were controlled for, smokers were, on average, 47% more likely to have spotting or bleeding than nonsmokers were over six cycles of oral contraceptive use, with higher levels of smoking associated with a greater frequency of spotting or bleeding. By the sixth cycle women who smoked > or = 16 cigarettes per day were almost three times more likely to have spotting or bleeding than were nonsmokers.
Cigarette smoking adversely affects cycle control among oral contraceptive users, possibly by increasing estrogen catabolism. Although these findings also raise the possibility that oral contraceptive efficacy may also be impaired in smokers, an immediate concern is that oral contraceptive users who have spotting and bleeding are more likely to discontinue their use, placing them at risk of unintended pregnancy.
由于吸烟具有多种抗雌激素作用，我们研究了吸烟可能对口服避孕药女性的点滴出血和出血情况产生不利影响的可能性。
进行了三项开放标签的随机临床试验，涉及2956名口服避孕药使用者的16506个周期。
吸烟者报告的点滴出血或出血频率始终高于非吸烟者。在控制了口服避孕药使用的近期性和一致性以及孕激素成分后，在六个周期的口服避孕药使用中，吸烟者出现点滴出血或出血的可能性平均比非吸烟者高47%，吸烟量越高，点滴出血或出血的频率越高。到第六个周期，每天吸烟≥16支的女性出现点滴出血或出血的可能性几乎是非吸烟者的三倍。
吸烟对口服避孕药使用者的周期控制有不利影响，可能是通过增加雌激素分解代谢。尽管这些发现也增加了吸烟者口服避孕药效果可能受损的可能性，但一个直接的问题是，出现点滴出血和出血的口服避孕药使用者更有可能停止使用，使她们面临意外怀孕的风险。
