Truitt S T, Fraser A B, Grimes D A, Gallo M F, Schulz K F
Family Health International, P. O. Box 13950, Research Triangle Park, North Carolina 27709, USA.
Cochrane Database Syst Rev. 2003(2):CD003988. doi: 10.1002/14651858.CD003988.
Contraception for women who are breastfeeding is a public health issue of global importance. Each year over 100 million women make decisions about beginning or resuming contraception after childbirth. These decisions include both the choice of contraceptive method and the time at which its use begins, both of which continue to be debated by experts. Choices of contraception may be limited for lactating women due to concerns about hormonal effects on quality and quantity of milk, passage of hormones to the infant, and infant growth. Ideally, the contraceptive method chosen should not interfere with lactation. Additionally, because the return of menstruation and ovulation can be unpredictable in breastfeeding women, the timing of contraception initiation is important.
To determine the effect of combined oral contraceptives and progestin-only contraceptives on lactation. The a priori hypothesis is that combined oral contraception impairs lactation, making it less appropriate than progestin-only or nonhormonal contraception for breastfeeding women.
We used PUBMED, POPLINE, EMBASE, LILACS, and Cochrane Controlled Trials Register computer searches, supplemented by review articles and contact with investigators.
We sought all randomized controlled trials, reported in any language, that included any form of hormonal contraception compared with another form of hormonal contraception, nonhormonal contraception, or placebo during lactation. Hormonal contraception could include combined oral or injectable contraceptives, progestin-only oral or injectable contraceptives, hormonal implants, or hormonal intrauterine devices. Study participants included breastfeeding women of any age or parity who desired contraception.
We evaluated the methodological quality of each report and sought to identify duplicate reporting of data from multicenter trials. We abstracted data onto data collection forms. Principal outcome measures included quantity of milk; biochemical analysis of milk composition; initiation, maintenance and duration of lactation; infant growth; efficacy of contraceptive method while breastfeeding; and timing of contraception initiation and its effects on lactation. Because the trials did not have uniform interventions, often lacked quantifiable outcomes, and had poor methodological quality, we could not aggregate the data in a meta-analyses.
Seven reports from five randomized controlled trials met our inclusion criteria. Most of the five trials did not specify their method used to generate a random sequence, method of allocation concealment, blinding of treatments, or use of an intention-to-treat analysis. Additionally, high loss to follow-up rates invalidated at least two studies. The findings from two reports comparing oral contraceptives to placebo during lactation were conflicting. Another trial found no inhibitory effects on lactation from progestin-only contraceptives. Finally, the WHO trial found no effect of progestin-only contraceptives on lactation but a decline in breast milk volume from combination contraceptives during lactation. High loss to follow-up rates, however, undermine the credibility of the WHO trial. No significant differences in infant growth or weight appeared in any of the included trials as a result of the use of hormonal contraception during lactation.
REVIEWER'S CONCLUSIONS: Evidence from randomized controlled trials on the effect of hormonal contraceptives during lactation is limited and of poor quality; results should be interpreted with caution. The existing randomized controlled trials are insufficient to establish an effect of hormonal contraception, if any, on milk quality and quantity. Evidence is inadequate to make recommendations regarding hormonal contraceptive use for lactating women. At least one properly conducted randomized controlled trial of adequate size is urgently needed to address this question.
哺乳期妇女的避孕是一个具有全球重要性的公共卫生问题。每年有超过1亿名妇女在产后做出开始或恢复避孕的决定。这些决定包括避孕方法的选择及其开始使用的时间，而这两个方面仍在专家之间存在争议。由于担心激素对乳汁质量和数量的影响、激素传递给婴儿以及婴儿生长，哺乳期妇女的避孕选择可能会受到限制。理想情况下，所选择的避孕方法不应干扰哺乳。此外，由于哺乳期妇女月经和排卵的恢复可能不可预测，开始避孕的时间很重要。
确定复方口服避孕药和仅含孕激素避孕药对哺乳的影响。先验假设是复方口服避孕药会损害哺乳，使其对哺乳期妇女而言不如仅含孕激素或非激素避孕方法合适。
我们使用了PUBMED、POPLINE、EMBASE、LILACS和Cochrane对照试验注册库进行计算机检索，并辅以综述文章以及与研究人员的联系。
我们查找了所有以任何语言发表的随机对照试验，这些试验包括在哺乳期将任何形式的激素避孕与另一种形式的激素避孕、非激素避孕或安慰剂进行比较。激素避孕可包括复方口服或注射用避孕药、仅含孕激素的口服或注射用避孕药、激素植入物或激素宫内节育器。研究参与者包括任何年龄或产次且希望避孕的哺乳期妇女。
我们评估了每份报告的方法学质量，并试图识别多中心试验数据的重复报告。我们将数据提取到数据收集表格中。主要结局指标包括乳汁量；乳汁成分的生化分析；哺乳的开始、维持和持续时间；婴儿生长；哺乳期避孕方法的有效性；以及开始避孕的时间及其对哺乳的影响。由于试验没有统一的干预措施，常常缺乏可量化的结局，且方法学质量较差，我们无法在荟萃分析中汇总数据。
来自五项随机对照试验的七份报告符合我们的纳入标准。五项试验中的大多数未具体说明其用于生成随机序列的方法、分配隐藏方法、治疗的盲法或意向性分析的使用情况。此外，高失访率使至少两项研究无效。两份关于哺乳期口服避孕药与安慰剂比较的报告结果相互矛盾。另一项试验发现仅含孕激素避孕药对哺乳没有抑制作用。最后，世界卫生组织的试验发现仅含孕激素避孕药对哺乳没有影响，但复方避孕药在哺乳期会使母乳量减少。然而，高失访率削弱了世界卫生组织试验的可信度。在任何纳入试验中，由于哺乳期使用激素避孕，婴儿生长或体重均未出现显著差异。
关于哺乳期激素避孕效果的随机对照试验证据有限且质量较差；结果应谨慎解释。现有的随机对照试验不足以确定激素避孕对乳汁质量和数量是否有影响（如果有影响的话）。证据不足以就哺乳期妇女使用激素避孕提出建议。迫切需要至少一项规模适当且实施得当的随机对照试验来解决这个问题。
