ntresdk952 2010-1-19 11:32
荷爾蒙避孕藥物的好處可能超過避孕效果
作者：Laurie Barclay, MD
出處：WebMD醫學新聞
December 31, 2009 — 根據一篇由美國婦產科醫學會（ACOG）發佈的執業佈告，荷爾蒙避孕藥物的好處可能超過避孕效果，這篇佈告發表於2010年1月號的婦產科醫學期刊（Obstetrics Gynecology）。
加拿大安大略京斯敦Robert L. Reid醫師在一篇新聞稿中表示，長久以來，我們已經知道荷爾蒙避孕藥物所帶來的健康好處超過避孕效果。這些建議檢驗支持非避孕使用荷爾蒙避孕藥物來治療特定情況的科學數據。
在美國，超過80%女性在她們的懷孕年齡使用某些型式的荷爾蒙避孕方法，例如口服避孕藥物（OC）、貼片、單桿黃體激素與其他植入物、注射劑、陰道環以及子宮內裝置。除了避免非預期懷孕之外，荷爾蒙避孕藥物已經以非許可適應症外的方式有效治療經期異常，包括痛經與經血過多。
高達90%的年輕女性有痛經的問題，這是女性經常無法上學或上班的主要原因。如果未經治療，經血過多可能造成貧血。有3/4痛經的女性對合併OC治療有很好的反應，而陰道環也有相等的療效。
經血過多最符合經濟效益的治療策略，可能是合併OC治療一年，之後使用levonorgestrel子宮內裝置。Levonorgestrel子宮內裝置在治療嚴重經血過多上，顯然比週期使用norethindrone更有效。較長時間（84天）使用週期性合併OC降低經血達40~50%以上。然而，延長週期OC可能造成點狀出血機率更高。
某些證據指出，合併ethinyl estradiol與drospirenone可能降低經前精神異常症狀。
使用合併雌性激素及黃體激素的避孕藥物與發生子宮內膜癌（相較於從未使用者，風險下降50%）、卵巢癌（風險下降27%）以及大腸直腸癌風險下降有關。目前的研究數據顯示，長期使用OC，即使停用後，與長達20年的子宮內膜及卵巢癌風險下降有關。目前或最近使用口服避孕藥物可能短期避免發生大腸直腸癌（風險下降18%）。
除此之外，合併型避孕藥物阻斷雄性激素產生，可能因此降低多毛症與面皰。在治療多毛症上，含有drospirenone 或cyproterone acetate的避孕藥物是最有效的，但是在治療面皰方面，所有合併型避孕藥物的效果相似。
荷爾蒙避孕藥物在預防經期偏頭痛、治療因子宮內膜異位造成的骨盆腔疼痛、以及因為子宮纖維囊腫造成的出血上，可能也有理論上或實際上的好處。延長週期或持續使用荷爾蒙避孕藥物可能降低經期偏頭痛的頻率，但是合併型OC已經證實可能增加35歲以上吸菸或有局部神經功能病徵的女性中風風險，這些女性應該避免使用合併型OC。
Reid醫師表示，合併型口服避孕藥物在正常化週期異常、降低經前精神症狀、改善面皰、以及讓女性免於在不方便的時候月經來潮，例如出差、休假或是蜜月時是有效的。雖然較新型的荷爾蒙避孕藥物在非適應症以外的研究數據並不多，專家們表示他們可能與治療相似狀況且更多研究的藥物一樣有效。
根據科學證據（A級）的特定建議如下：
* 合併型OC不應該用於治療已存在的或功能性卵巢囊腫
* 使用合併型荷爾蒙避孕藥物已證實可降低子宮內膜癌與卵巢癌
* 合併型OC已證實可以調控與降低經期出血、治療痛經、降低經前精神異常以及治療面皰。
根據有限或結果不完全一致之科學證據（B級）特定建議為：
* 根據目前有限的證據，合併型OC與發生子宮肌瘤的風險增加無關。
* 計畫懷孕的女性，可考慮以荷爾蒙避孕藥物作為治療經血過多的選擇。
由ACOG提出的成效評量為在沒有使用荷爾蒙避孕藥物的禁忌症下，使用荷爾蒙避孕藥物治療經血過多以及/或是痛經症狀，且希望保留生殖功能的女性百分比。
Benefits of Hormonal Contraception May Extend Beyond Pregnancy Prevention
By Laurie Barclay, MD
Medscape Medical News
December 31, 2009 — The benefits of hormonal contraceptives may extend beyond pregnancy prevention, according to a practice bulletin issued by the American College of Obstetricians and Gynecologists (ACOG) and published in the January 2010 issue of Obstetrics Gynecology.
"We've known for many years that hormonal contraceptives have health advantages beyond preventing pregnancy," lead author Robert L. Reid, MD, from Kingston, Ontario, Canada, said in a news release. "These recommendations examine the scientific data supporting the noncontraceptive uses of hormonal contraceptives to treat specific conditions."
During their reproductive years, more than 80% of women in the United States use some form of hormonal contraception, such as oral contraceptive (OC) pills, patches, single-rod progestin and other implants, injections, vaginal rings, and the intrauterine device. In addition to preventing unplanned pregnancies, hormonal contraceptives are used off-label to effectively treat menstrual disorders including dysmenorrhea and menorrhagia.
Up to 90% of young women report dysmenorrhea, which is a leading cause of school and work absenteeism among women. If left untreated, menorrhagia can cause anemia. Approximately three quarters of women with dysmenorrhea respond favourably to combined OC treatment, and the vaginal ring may be equally effective.
The most cost-effective treatment strategy for menorrhagia may be combined OC use for 1?year, followed by use of a levonorgestrel intrauterine device. The levonorgestrel intrauterine system appears to be better than cyclical norethindrone for the treatment of heavy bleeding. Cyclic combined OCs decrease menstrual blood loss by 40% to 50%, or even more, for extended-cycle (84-day) OCs. However, extended-cycle OCs may cause higher rates of spotting.
Some evidence suggests that the combination of ethinyl estradiol plus drospirenone may reduce symptoms of premenstrual dysphoric disorder.
Use of combined contraceptives containing both estrogen and progesterone is associated with a lower risk for the development of endometrial cancer (50% reduction in risk vs never-use), ovarian cancer (27% decrease in risk), and colorectal cancers. Studies to date suggest that longer duration of OC use is linked to a decreased risk for the development of endometrial and ovarian cancer for up to 20 years after discontinuing use. Current or recent use of oral contraception also may protect against colorectal cancer in the short term (18% decrease in risk).
In addition, combined contraceptives block androgen production and may therefore reduce hirsutism and acne. Contraceptives containing drospirenone or cyproterone acetate may be most effective for treatment of hirsutism, but all combined contraceptives appear to be similarly effective against acne.
Hormonal contraceptives may also be of theoretic or actual benefit in preventing menstrual migraines, treating pelvic pain caused by endometriosis, and treating bleeding from uterine fibroids. Extended-cycle or continuous hormonal contraception may reduce the frequency of menstrual migraine, but combined OCs have been associated with possible increased stroke risk in women with migraine who are 35 years or older, who smoke, or who have focal neurologic signs. Combined OCs should therefore be avoided in these women.
"Combined oral contraceptives are effective in normalizing irregular periods, reducing symptoms of premenstrual dysphoric disorder, improving acne, and allowing women to avoid having their period at inconvenient times, such as during a business trip, vacation, or honeymoon," Dr. Reid said. "Although there is little data on the newer forms of hormonal contraception in terms of their off-label benefits, experts suggest that they may be as effective as the more studied ones in treating the same conditions."
Specific recommendations, based on good, consistent scientific evidence (level A), are as follows:
Combined OCs should not be used to treat existing, functional ovarian cysts.
Combined hormonal contraceptive use has been shown to lower the risk for endometrial and ovarian cancer.
Combined OCs have been shown to regulate and decrease menstrual bleeding, to treat dysmenorrhea, to reduce symptoms of premenstrual dysphoric disorder, and to treat acne.
Specific recommendations based on limited or inconsistent scientific evidence (level B), are as follows:
Combined OCs are not associated with increased risk for the development of uterine leiomyoma, based on limited evidence to date.
In women who may wish to become pregnant, hormonal contraception should be considered for treatment of menorrhagia.
A performance measure proposed by the ACOG is the percentage of women wishing to preserve reproductive potential who are using hormonal contraception to treat symptoms of menorrhagia and/or dysmenorrhea, provided they have no contraindications to use of hormonal contraception.
Obstet Gynecol. 2010;115:206-218.