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Optimal duration of exclusive breastfeeding

  1. Michael S Kramer*,
  2. Ritsuko Kakuma

Editorial Group: Cochrane Pregnancy and Childbirth Group

Published Online: 21 JAN 2002

Assessed as up-to-date: 29 DEC 2006

DOI: 10.1002/14651858.CD003517


How to Cite

Kramer MS, Kakuma R. Optimal duration of exclusive breastfeeding. Cochrane Database of Systematic Reviews 2002, Issue 1. Art. No.: CD003517. DOI: 10.1002/14651858.CD003517.

Author Information

  1. McGill University, Faculty of Medicine, Montreal, Quebec, Canada

*Michael S Kramer, Faculty of Medicine, McGill University, 1020 Pine Avenue West, Montreal, Quebec, H3A 1A2, Canada. michael.kramer@mcgill.ca.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 21 JAN 2002

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This is not the most recent version of the article. View current version (15 AUG 2012)

 

Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

Although the health benefits of breastfeeding are widely acknowledged, opinions and recommendations are strongly divided on the optimal duration of exclusive breastfeeding. Much of the debate has centered on the so-called 'weanling's dilemma' in developing countries: the choice between the known protective effect of exclusive breastfeeding against infectious morbidity and the (theoretical) insufficiency of breast milk alone to satisfy the infant's energy and micronutrient requirements beyond four months of age.

Objectives

To assess the effects on child health, growth, and development, and on maternal health, of exclusive breastfeeding for six months versus exclusive breastfeeding for three to four months with mixed breastfeeding (introduction of complementary liquid or solid foods with continued breastfeeding) thereafter through six months.

Search methods

We searched the following databases: MEDLINE (as of 1966), Index Medicus (before 1966), CINAHL, HealthSTAR, BIOSIS, CAB Abstracts, EMBASE-Medicine, EMBASE-Psychology, EconLit, Index Medicus for the WHO Eastern Mediterranean Region, African Index Medicus, LILACS (Latin American and Caribbean Health Sciences), EBM Reviews-Best Evidence, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials. The two searches yielded a total of 2668 unique citations. Contacts with experts in the field yielded additional published and unpublished studies. The updated review extended the literature searched until December 2006 and yielded 835 additional unique citations.

Selection criteria

We selected all internally-controlled clinical trials and observational studies comparing child or maternal health outcomes with exclusive breastfeeding for six or more months versus exclusive breastfeeding for at least three to four months with continued mixed breastfeeding until at least six months. Studies were stratified according to study design (controlled trials versus observational studies), provenance (developing versus developed countries), and timing of compared feeding groups (three to seven months versus later).

Data collection and analysis

We independently assessed study quality and extracted data.

Main results

We identified 22 independent studies meeting the selection criteria: 11 from developing countries (two of which were controlled trials in Honduras) and 11 from developed countries (all observational studies). Definitions of exclusive breastfeeding varied considerably across studies. Neither the trials nor the observational studies suggest that infants who continue to be exclusively breastfed for six months show deficits in weight or length gain, although larger sample sizes would be required to rule out modest differences in risk of undernutrition. In developing-country settings where newborn iron stores may be suboptimal, the evidence suggests that exclusive breastfeeding without iron supplementation through six months may compromise hematologic status. Based on studies from Belarus, Iran, and Nigeria, infants who continue exclusive breastfeeding for six months or more appear to have a significantly reduced risk of gastrointestinal and (in the Iranian and Nigerian studies) respiratory infection. No significant reduction in risk of atopic eczema, asthma, or other atopic outcomes has been demonstrated in studies from Finland, Australia, and Belarus. Data from the two Honduran trials and from observational studies from Bangladesh and Senegal suggest that exclusive breastfeeding through six months is associated with delayed resumption of menses and, in the Honduran trials, more rapid postpartum weight loss in the mother.

Authors' conclusions

We found no objective evidence of a 'weanling's dilemma'. Infants who are exclusively breastfed for six months experience less morbidity from gastrointestinal infection than those who are mixed breastfed as of three or four months, and no deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for six months or longer. Moreover, the mothers of such infants have more prolonged lactational amenorrhea. Although infants should still be managed individually so that insufficient growth or other adverse outcomes are not ignored and appropriate interventions are provided, the available evidence demonstrates no apparent risks in recommending, as a general policy, exclusive breastfeeding for the first six months of life in both developing and developed-country settings. Large randomized trials are recommended in both types of setting to rule out small effects on growth and to confirm the reported health benefits of exclusive breastfeeding for six months or beyond.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Optimal duration of exclusive breastfeeding

Exclusive breastfeeding for six months (versus three to four months) reduces gastrointestinal infection, does not impair growth, and helps the mother lose weight.

The results of two controlled trials and 18 other studies suggest that exclusive breastfeeding (no solids or liquids besides human milk, other than vitamins and medications) for six months has several advantages over exclusive breastfeeding for three to four months followed by mixed breastfeeding. These advantages include a lower risk of gastrointestinal infection, more rapid maternal weight loss after birth, and delayed return of menstrual periods. No reduced risks of other infections or of allergic diseases have been demonstrated. No adverse effects on growth have been documented with exclusive breastfeeding for six months, but a reduced level of iron has been observed in developing-country settings.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

純母乳哺育的理想期間

雖然很多人都知道哺育母乳對健康的好處,但是有關純母乳哺育的理想期間仍明顯存在著許多不同的觀點與建議。在開發中國家,很多爭議都集中在所謂「離乳的兩難」:得在純母乳哺育以對抗傳染病的發生與母乳之營養和能量不足以供給超過4個月大之後的嬰兒以滿足其需求兩者中做出抉擇

目標

比較連續6個月哺餵純母乳和連續3 – 4個月哺餵純母乳後接著6個月哺餵母乳和另外補充的水分及固體食物對於孩童的健康、生長、發育及母親健康的影響

搜尋策略

我們搜尋了下列的資料庫:MEDLINE(如1966年份的)、Index Medicus(1966年之前)、CINAHL、HealthSTAR、BIOSIS、CAB Abstracts、EMBASEMedicine、EMBASEPsychology、EconLit、Index Medicus for the WHO Eastern Mediterranean Region、African Index Medicus、LILACS(Latin American and Caribbean Health Sciences)、EBM ReviewsBest Evidence、the Cochrane Database of Systematic Reviews,以及the Cochrane Central Register of Controlled Trials。這2種搜尋結果共得到總數為2668篇的單獨引用。跟該領域的專家接觸後得到額外發表過與未發表的研究。這更新的文獻回顧將搜尋的文章延伸到2006年12月並獲得另外835篇單獨引用

選擇標準

我們選擇了比較連續6個月哺餵純母乳和連續至少3 – 4個月哺餵純母乳後接著6個月哺餵母乳和另外補充的水分及固體食物之孩童和母親健康結果的內部控制臨床試驗和觀察行研究。根據研究設計(受控制的試驗與根據觀察的研究相較)、來源(開發中國家與已開發國家相較),以及接受比較的哺乳組之取樣時機(3到7個月與更後期相較)

資料收集與分析

我們獨立評估研究的品質與選用的資料

主要結論

我們找出22個符合選擇標準的獨立研究:開發中國家的研究有11個(其中有2個是在宏都拉斯的控制試驗),已開發國家的研究者11個(全部都是觀察型研究)。在不同研究之間對於純母乳哺育的定義有很大的差異。雖然這些控制試驗和觀察型研究,都不認為接受純母乳哺育6個月後的嬰兒會在身高或體重方面發育不足,不過仍需更大的樣本以排除營養不良風險的差異。在開發中國家新生兒體內的鐵貯存量可能還未達最佳狀態,證據顯示在未補充鐵的情況下,經過6個月的純母乳哺育後有可能會有不正常的血液狀態。根據白俄羅斯、伊朗以及奈及利亞的研究,持續接受純母乳哺育達6個月或更久的嬰兒,在腸胃方面與(伊朗與奈及利亞的研究)呼吸道感染的風險明顯地降低。芬蘭、澳大利亞以及白俄羅斯的研究,顯示異位性濕疹、氣喘或是其他過敏症的風險並沒有明顯的降低。另外根據兩個宏都拉斯的試驗以及孟加拉共和國與塞內加爾的觀察型研究顯示6個月的純母乳哺育與延遲恢復月經有關,宏都拉斯的試驗則顯示與母親產後減重較快有關

作者結論

我們並沒有發現任何「離乳的兩難」的客觀證據。接受6個月純母乳哺育的嬰兒比接受3 – 4個月混合哺育的嬰兒較少罹患腸胃道感染,而且不論是在開發中或已開發國家接受6個月或更長之純母乳哺育的嬰兒都沒有生長發育不良的情形。此外,這些嬰兒的母親有更長的哺乳期無月經避孕。雖然嬰兒還是應該視個別情形照顧以避免忽略發育不良或其他不良的結果並提供適當的處置,但目前的證據顯示在開發中和已開發國家產後6個月哺餵純母乳的建議不會有明顯的風險。建議在開發中國和已開發國家規劃大型隨機試驗已排除至少6個月的純母乳哺育對生長之輕微影響並確認它對健康的助益

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌

總結

為期6個月(相較於3到4個月)的純母乳哺育可以降低腸胃道感染而不會影響生長,並且可幫助母親減輕體重。這2個控制試驗與其他18個研究結果顯示為期6個月的純母乳哺育(母乳之外,沒有任何的液體或固體,除了維他命或藥物),比起3 – 4個月哺餵純母乳再混合哺乳,具有許多優點,這些優點包括腸胃道感染風險較低、母親產後減重速度較快以及可以延後恢復月經週期。其他感染或是過敏疾病的風險並未降低。目前並未記載到6個月的純母乳哺育對生長會有不良的影響,但是在開發中國家則有觀察到體內含鐵量較低的現象