Fraser I S
Department of Obstetrics and Gynaecology, University of Sydney, NSW, Australia.
Contraception. 1994 Apr;49(4):399-420. doi: 10.1016/0010-7824(94)90035-3.
The main raison d'être for the development of once-a-month injectable contraceptives is the need for a long-acting method which produces a regular vaginal bleeding pattern. Although many women will successfully tolerate the amenorrhea or irregular bleeding which frequently accompany use of long-acting progestogen-only methods, there is a substantial minority, especially in certain ethnic groups, who find this unacceptable. The extensive literature does indicate that although combined estrogen-progestogen once-a-month injectables produce much more regular bleeding patterns than long-acting injectables like depot-medroxyprogesterone acetate, the patterns are not entirely normal. Detailed studies by the World Health Organization have demonstrated some deviation from normal menstrual patterns by users of the two once-a-month injectables, Cyclofem and Mesigyna. For example, 23.5% of Cyclofem and 25.2% of Mesigyna users experience irregular bleeding between 3 and 6 months of use compared with 4.8% of untreated women, and 13.3% of Cyclofem and 11.1% of Mesigyna users experience prolonged bleeding compared with 2.3% of untreated women. Comparable figures are much worse for DMPA users with a 35.7% incidence of irregular and 27.7% incidence of prolonged bleeding after similar duration of use. Bleeding patterns with all long-acting methods tend to improve with time. Overall group data for once-a-month injectable users are reasonably close to those of untreated women with, for example, a median of 15.6 days (5th and 95th percentiles: 7.5 and 26; confidence limits) of bleeding or spotting per 90-day reference period compared with a median of 18.5 days (5th and 95th percentiles: 12.2 and 25.5) for untreated women. Twelve-month life table discontinuation rates for menstrual bleeding disturbances are lower than expected for most progestogen-only methods at 2.1-5.2% for Cyclofem and 0.8-4.2% for Mesigyna for amenorrhea, and 6.3-12.7% for Cyclofem and 7.5-12.0% for Mesigyna for bleeding-related reasons. Once-a-month injectable contraceptives produce vaginal bleeding patterns much closer to normal than other injectables, but there are still significant deviations which lead to some discontinuation for menstrual reasons. Hence, full explanation and counselling about possible menstrual changes are still essential for all intending users of these methods.
每月注射一次的避孕药具研发的主要目的是满足对长效避孕方法的需求，这种方法能产生规律的阴道出血模式。尽管许多女性能够成功耐受长效仅含孕激素方法使用过程中经常伴随的闭经或不规则出血，但仍有相当一部分人，尤其是某些特定种族群体的女性，认为这难以接受。大量文献表明，尽管复方雌激素 - 孕激素每月注射一次的避孕药具比醋酸甲羟孕酮长效注射剂等长效注射剂产生的出血模式更规律，但这些模式并非完全正常。世界卫生组织的详细研究表明，使用两种每月注射一次的避孕药具Cyclofem和Mesigyna的女性，其月经模式与正常情况存在一些偏差。例如，使用Cyclofem的女性中有23.5%、使用Mesigyna的女性中有25.2%在使用3至6个月期间出现不规则出血，而未治疗女性的这一比例为4.8%；使用Cyclofem的女性中有13.3%、使用Mesigyna的女性中有11.1%出现经期延长，而未治疗女性的这一比例为2.3%。在使用相似时长后，醋酸甲羟孕酮使用者的可比数据要糟糕得多，不规则出血发生率为35.7%，经期延长发生率为27.7%。所有长效避孕方法的出血模式往往会随着时间推移而改善。每月注射一次的避孕药具使用者的总体组数据与未治疗女性的数据相当接近，例如，每90天参考期内出血或点滴出血的中位数为15.6天（第5和第95百分位数：7.5和26；置信区间），而未治疗女性的这一数据为18.5天（第5和第95百分位数：12.2和25.5）。因月经出血紊乱导致的12个月生命表停用率低于大多数仅含孕激素方法的预期，Cyclofem因闭经导致的停用率为2.1 - 5.2%，Mesigyna为0.8 - 4.2%；Cyclofem因出血相关原因导致的停用率为6.3 - 12.7%，Mesigyna为7.5 - 12.0%。每月注射一次的避孕药具产生的阴道出血模式比其他注射剂更接近正常，但仍存在显著偏差，这导致一些使用者因月经原因停药。因此，对于所有打算使用这些方法的人来说，全面解释并提供关于可能出现的月经变化的咨询仍然至关重要。
