泌乳的开始 —— 怀孕
对于许多女性来说，乳房疼痛是怀孕的早期迹象。乳房的发育在怀孕期间完成了发育，而乳汁的生成则开始于孕中期。如果怀孕在15-16周后终止，乳房就已经有初乳(早期的乳汁)就已经存在了。
一些女性选择因为。推荐患糖尿病的女性采用这个做法，因为她们在产后，奶量增加（“下奶”）可能会慢一点，而她们的婴儿可能会发生低血糖。产前挤出的初乳可以储存起来，万一婴儿需要补奶，就可以喂给他们。
高危妊娠的母亲、或者担心能否有足够奶量的母亲，也可以选择在怀孕的最后几周挤出初乳。通常建议不要在36周之前开始挤奶，除非早产迫在眉睫。你在产前挤出的初乳量并不预示着你分娩后产出足够奶量的能力。
出生后(第1-3天) —— 泌乳快速启动！
怀孕期间，乳汁的生成受到胎盘分泌的孕激素的抑制。一旦婴儿出生并且胎盘娩出，孕激素水平就迅速下降，再加上高水平的催乳素，就使泌乳全面启动。
残留的胎盘组织会减少甚至停止产奶。如果你的产奶量不明原因的低，并且本应停止排恶露了而你仍然大量或不规律地出血，请咨询你的助产士团队或医生。清除了胎盘的残留组织通常会让产奶恢复正常。
图|国际母乳会中国图片库
母亲们往往在产后两三天时开始注意到“大量产奶的启动”(也称为“下奶”)的迹象。你可能会经历一两天的:
乳房疼痛
乳房温度变高
乳房不适
乳房肿胀
乳房增大
轻微发烧
你感到的不适主要是由于乳汁量的激增引起的组织肿胀。不要惊慌——你的乳房不会一直这样不舒服的！随着乳房产奶量调整到婴儿所需后，肿胀就会缓解。如果给婴儿哺乳或者挤奶都不能让你尽快感觉舒服些，你还可以采取其它措施处理涨奶。
以下情况可能会延迟大量产奶的启动（“下奶”）:
母亲初产
母亲难产
你可能读到过，超重或肥胖(体重指数较高，尤其是BMI超过30)会带来母乳喂养的问题。目前尚不清楚体重指数较高本身是否是母乳喂养的一个问题，毕竟很多体重指数高的女性母乳喂养得很容易。我们明确知道的是，一些与较高体重指数相关的病症，如糖尿病和代谢综合征，可能会延迟产后初期的“下奶”(奶量增加)。这会使母乳喂养的挑战更大。
产后第3-4天起，只有排出乳汁，才能继续产奶
一直到产后第3-4天，乳汁的生成都完全是由荷尔蒙控制，并且会自动发生，不管你有没有母乳喂养。但在产后第3-4天之后，另一个机制就开始发挥作用了。乳汁只有从乳房中排出，才能继续生成。排出的越多，生成的就越多。这能让你的身体适应来喂饱一个或多个孩子。只要有足够的乳汁排出，就有可能纯母乳喂养双胞胎或三胞胎！如果你完全不母乳喂养或者不挤奶，你的泌乳将在产后约两周内停止。
尽早排出乳汁
产后初期排出的奶量对以后的产奶量很重要。对于早产来说，与产后六小时开始挤奶相比，产后一小时内开始挤奶会使六周后奶的量更多。
如果你的宝宝早期有任何不能有效喂养的风险因素，例如:
早产
小于胎龄儿
身体不适
黄疸
嗜睡
和你分离
那么尽早、频繁地挤奶将有助于保证有足够的奶量来满足他们目前和之后的需求。你可以点击“阅读原文”看到一个有用的视频。
如果母亲有泌乳量不足的风险因素，通过产后尽早频繁地排出乳汁，可以给她们的乳汁分泌尽可能开个好头。
这些风险因素包括:
既往产奶量低史
既往乳房放疗或手术史
多囊卵巢综合征
甲状腺问题(甲减或甲亢)
荷尔蒙引起的不孕史
乳房大小不一、双乳间距过大、孕期或产后乳房几乎没有变化
肥胖(体重指数超过30)
有这些风险因素的女性可能产出足够的奶量或只能产一部分奶量——除非你亲自尝试一下，否则你永远不知道你的乳房能产多少奶！如果你没有产出婴儿需要的全部奶量，你仍然可以和孩子享受亲密、快乐的喂养关系。
一些母亲在产后头几个月给婴儿母乳喂养的同时需要补充捐赠的母乳或配方奶，婴儿六个月左右开始添加辅食之后，就能减少或停止这些补充的奶，吃辅食的同时继续高高兴兴地母乳喂养。
频繁排出乳汁
足月健康的新生儿吃完第一口奶后会进入几个小时的睡眠。等他醒来之后就要频繁地哺乳，昼夜不停。大多数婴儿在出生后的前几周每24小时需要哺乳至少8-12次，每次都要用力吸吮和吞咽，才能获得足够的母乳并刺激母亲的奶量。如果你的宝宝还没有这么频繁或起劲地吃奶，而你的目标是纯母乳喂养，那么挤奶就很重要了。
随着乳汁在乳房中的积聚，母乳中一种被称为“哺乳反馈抑制因子”(FIL)的一种蛋白质，就开始减缓乳汁的生成了。充盈的乳房使产奶减慢，最终完全不产奶了。乳汁排出充分会使乳房产奶加快。这就是为什么如果你要增加奶量，重要的是不要等到乳房感觉很充盈了才喂奶或挤奶的原因。这会随着时间的推移减少产奶量。
不同的乳房，不同的喂养方式
乳房的存储容量在母乳喂养领域中是一个全新的概念，它很好地解释了母亲们本能地知道、但在教科书里却没有的东西！
一位母亲的“乳房存储容量”就是她的乳房最充盈时所能容纳的最大母乳量。它与乳房大小无关，也与母亲每天所能产出的总奶量无关。
为了理解乳房的存储容量，我们来假设一下：
阿丽莎和贝丝都有三个月大的宝宝，也都有足够的奶量。
阿丽莎的乳房可以容纳75毫升的母乳，贝丝的乳房可以容纳150毫升的母乳。
她们的宝宝每天都需要大约750毫升的母乳(这是一个平均量。有些婴儿每天可能需要1200毫升之多)。
阿丽莎的宝宝需要每24小时至少哺乳10次才能吃到这么多量的母乳，而 贝丝的宝宝只需要哺乳5到6次就能吃到同样的母乳量。【一天内哺乳次数这么少并不常见——它只是广泛喂养方模式中的一个极端情况！】
两名婴儿都得到了他们所需的母乳量，并且都长得很好，但是他们有非常不同的哺乳方式。那假如阿丽莎和贝丝被告知她们的宝宝“应该”在24小时内哺乳8次，会发生什么？
阿丽莎的宝宝会饥饿难耐。她已吃不到足够的母乳，如果继续这样下去，阿丽莎的奶量就会减少，因为泌乳抑制反馈因子FIL会在充盈的乳房中起效。过了产后的最初几周，当奶量维持在一个稳定的水平时，再增加奶量可能就很难了。
而贝丝的宝宝呢，则会很烦躁，因为妈妈在他一点儿都不想再喝奶时还一直试着喂他！
阿丽莎和贝丝都可以成功地母乳喂养她们的宝宝，只要她们的喂奶模式适应各自的乳房存储容量即可。
贝丝的乳房存储容量较大，所以她的喂奶方式更灵活。她的宝宝可能每天的哺乳次数要比阿丽莎的宝宝少，更有可能每次只吃一边乳房，还可能更早地开始睡长觉。她可以选择在宝宝愿意的时候喂得更频繁些。
阿丽莎的喂养方式就没那么灵活了，因为如果不频繁地哺乳，她的乳房就会充盈，没有足够的空间来产更多的奶。她的宝宝在纯母乳喂养期间可能会日夜频繁地哺乳，而且大多时候可能两边乳房都要吃。
大多数婴儿需要每24小时哺乳至少8-12次，重要的是要确保在产后最初几周内频繁地哺乳，因为这段时间奶量正在逐步建立起来。之后随着效率的提高，大多数婴儿花在哺乳上的时间会减少。一些婴儿也会明显减少哺乳的频率。
大多数母亲从不需要担心甚至是考虑她们的乳房存储容量，因为婴儿在出色地为她们解决这个问题！健康茁壮成长的足月婴儿能够选择他们自己的哺乳模式，既适应母亲的乳房又满足他们成长时的自身所需。如果婴儿长得很好，看起来也很满足，那么他们的哺乳模式就是为自己量身定制的。
母乳中的脂肪
这是一个经常让父母担心的话题，因为在很多家庭中流传着“前奶”和“后奶”之间区别的一知半解的信息。
我们从研究中得知:
乳房使乳脂处于一个稳定的水平。母乳中脂肪的种类与母亲饮食中脂肪的种类有一定的关系，但是脂肪的量与她的饮食无关。
哺乳开始时吃到的母乳(通常称为“前奶”)比哺乳到最后吃到的母乳(通常称为“后奶”)脂肪含量要低。随着乳房被排软，母乳中的脂肪含量就会增加，因为更多脂肪滴被“挤压”到乳房前部并从乳头流出。
一次哺乳开始时母乳中的脂肪水平取决于上次哺乳后到这次哺乳时的时间间隔。两次哺乳的间隔越长，下一次哺乳开始时的脂肪水平就越低。
父母们经常担心，或者被告知，他们的孩子可能没有吃到足够的脂肪(这通常被描述为“吃了太多的前奶”)。
研究表明，健康茁壮成长的足月婴儿很擅长平衡自己的饮食。当他们摄入了足够的热量时，就会停止吃奶。当母乳中的脂肪含量较高时，他们吃的奶量就会少些。而当脂肪含量较低时，他们就会吃得多些。母乳中脂肪含量的变化不是问题——什么样的母乳都很好！它能让婴儿在一开始吃奶时解渴，如果他们还想吃的话，就用奶油“甜点”完成一餐。
少数婴儿如果有以下情况，母乳中脂肪的平衡可能会成为他们的问题：
在婴儿还没吃饱前，就不让他继续在乳房上吃奶了；
奶量太多。这种情况下，婴儿会长得很快(他们的生长曲线在生长图上向上跨越了数个百分位) ，还可能和乳汁的流速在奋战，呛咳着松开乳房，吐奶，很难受。你可以在这里找到实用的技巧来帮助婴儿对付乳汁流速过快。
不管哪种情况，婴儿都可能吃不到足够的脂肪来减缓母乳通过肠道时的转运。母乳冲过肠道时，可能快过婴儿消化母乳中乳糖的速度。乳糖就留在肠道中发酵，产生了绿色、起泡、喷射状的便便，胀气(放屁)以及严重的不适。
婴儿如果拉黄色便便并且也很舒服，那他们的喂养就不存在任何脂肪平衡的问题。婴儿如果生长速度慢于预期，总的来说是需要吃更多母乳的，而不仅仅是吃更多脂肪。这些婴儿应该去看医生排除潜在的健康问题。
多少母乳量？
出生后的第一个24小时里，初乳的量很少，但足够婴儿喝了。每次平均的喂奶量约为7毫升(1勺半)。这是因为足月儿还不太饿——他们出生时体内自带粮食储备。他们不需要液体——在出生后前几天他们会排出多余的水分(这就是为什么大多数婴儿会掉一点体重)。初乳主要起免疫保护作用，而不是用来饱腹的食物。它覆盖到婴儿的肠道内壁以防病原体侵入，刺激婴儿自身的免疫系统，并提供给婴儿高效、定量的生长因子、激素、活性免疫细胞和其它成分，这些是人工配方奶粉无法企及的。
初乳量少而粘稠，让婴儿在对付更大量的母乳之前有了一个练习吃奶的机会。然后他们就得对付更大量的母乳了。初乳的量增长很快，在产后最初几天内，每天都几乎翻倍。如果你需要在产后第一天挤奶，可以用注射器来收集成滴的母乳。注射器很快就太小无法容纳日益增长的母乳量了。到产后第五天，婴儿可能每顿摄入60毫升(2盎司)或更多的奶量。
如果你在挤奶，例如是因为婴儿早产，下列数据有助于你知道努力的目标是多少：
出生后第一周结束时，每24小时产500毫升母乳
出生后第二周或第三周结束时，每24小时产750毫升母乳
婴儿可能还不需要这么多母乳，但现在就把目标定为纯母乳喂养，你才会在今后的母乳喂养时光里有足够的奶量来满足他们。
母乳产量从产后1~6个月左右会保持稳定，在每24小时约600-1200毫升之间。婴儿开始吃辅食后，随着饮食中其它食物逐渐取代母乳，母乳产量开始下降。如果你在产后一个月时产出了婴儿需要的奶量，就有可能会持续产这么多奶，只要婴儿不断地吸出足够的奶量、你没有怀孕、也没有服用个别影响奶量的药物即可。含有黄体酮的避孕方法可能会降低一些妇女的产奶量。
图|国际母乳会中国图片库
母乳是如何变化的
如果你在挤奶，到产后第四天左右，就能看到乳汁从粘稠、透明的黄色或橙色初乳变成较稀的白色或带点蓝色的“过渡乳”。你的乳汁成分正在改变，以适应婴儿对更多能量的需求。只要你在母乳喂养或挤奶，乳汁每一天都会变化，以顺应婴儿的各个发育阶段、你或婴儿接触到的任何疾病、甚至白天或晚上分泌的母乳都会不同。早产儿母亲的乳汁刚开始时不同于足月分娩母亲的乳汁，为的是满足她们婴儿的额外需求。
起步艰难后重回正轨
母乳产量在产后一个月左右达到高峰，大部分的奶量增长是在前两周内。许多母亲发现过了产后前几周再增加奶量会变得更难——有些情况下甚至不可能增加。这就是为什么如果有任何迹象表明婴儿获得足够的母乳存在问题，尽早获得良好的哺乳支持就很重要，例如，如果你的宝宝:
不是每天都大便(在产后初期的4-6周内)
出生三天后尿布里有粉色结晶(尿酸盐)
出生后第四天结束时还没有拉黄色便便
出生后第五天比出生体重减轻了7% 以上
出生第五天后体重还在减轻
到出生第10-14天时尚未恢复到出生体重
一名国际母乳会的哺乳辅导或是婴儿喂养专家可以帮助你弄清楚是否产奶量出现了问题，或者(更为常见)你是否还未有效地哺乳。如果没有排出足够的奶量，你的产奶量就会有无法增加到婴儿所需水平的风险。挤奶给了你缓冲时间去解决任何哺乳问题。
如果产奶量上有问题，支持你母乳喂养的人可以帮助你制定一个计划，你最大限度地增加奶量的同时，还可以安全地喂养婴儿。你需要与婴儿的医疗保健人员密切合作来监测他们的成长和健康。
出生头几个月之后的泌乳
母亲有时被告知，她们的母乳在6个月或12个月以后就对婴儿没有价值了，但事实并非如此。直到一岁左右，母乳都是婴儿蛋白质和能量的主要来源，并在整个第二年及以后都继续助力儿童的健康和营养。
你的母乳会随着婴儿的成长来适应他们的需求。例如：
大约六个月之后，淀粉酶这种消化酶开始出现在母乳中，帮助婴儿消化淀粉类食物。
大约六个月之后，溶菌酶这种抗菌酶的水平就会在母乳中增加，当婴儿把食物和其它东西放进嘴里时，它会保护婴儿。
随着母乳的总产量从六个月左右开始逐渐减少，免疫球蛋白等关键免疫因子的水平随之增加，因此即使孩子喝的母乳减少了，他们每天也会得到同样数量的免疫物质。
母乳中脂肪、蛋白质和能量的水平在哺乳的第二年要比第一年更高。
哺乳期结束——退化离乳
只要乳汁从乳房中排出，母乳就会继续在乳房中生成。在泌乳早期，产奶量是相对脆弱的——假如停止排出乳汁，母亲的身体很快就停止产奶。而在泌乳后期，产奶能力会更稳定。例如，母亲在六个月后重返职场，就能确保她们的奶量经得起日复一日、周复一周日程安排的变化。泌乳后期，部分母乳喂养是可行的，即使你得轮班工作或要出差过夜。许多母乳喂养的学步儿和大龄儿童会离开家去和父亲或祖父母等同住过夜，回到母亲身边时再继续母乳喂养。
在最后一次母乳喂养或挤奶后，乳房至少需要40天才能达到完全“退化”(非哺乳期状态)。一些母亲发现她们最后一次喂奶之后的几个月甚至几年内还会漏奶或能挤出几滴乳汁。如果母乳量过多，或者你尽管没有怀孕，但间隔一段时间后又开始产奶了，请咨询医生。自发的乳汁分泌(溢乳)可能是某些药物的副作用，或是荷尔蒙失调的迹象。
要让儿童能按照自己的节奏离乳，往往要花几个月甚至几年的时间才做得到。孩子选择离乳的最常见时间是在他们两到三岁之间。产奶量会逐渐减少，到孩子吃最后一顿奶时，可能已经微乎其微了。母乳中的一些免疫成分随着奶量的减少而更浓缩，因此孩子还能从最后一滴母乳中受益。
How milk production works
Mothers have successfully fed their children for thousands of years of human history without understanding how it works. It's a bit like driving a car – as long as it's working well, you don't need to know what is going on under the bonnet!
If you are having breastfeeding problems, such as low milk supply or too much milk, or are wondering why your baby's feeding pattern is different from what you expected, it can help to understand more about the science of lactation (producing milk).
Most of the research that has ever been done on breastfeeding and human milk has been done in the last few years. It is a very exciting time for lactation science. Lots of things that experienced mothers have always known turn out to have a clear basis in the anatomy of the breast and the science of milk production, for example:
Each baby and mother pair is different
Healthy babies are the best judges of when and how to feed
The way to make more milk is to remove more milk
Getting ready – the developing breast
Breast development starts around the age of 10-12 years. From puberty, the breast grows a little with each menstrual cycle. Inside the breast, the branches and buds that will become milk ducts and alveoli (milk storage sacs) start to develop. Radiation or trauma to the chest at this stage can have an impact on later breast development.
Lactation begins – pregnancy
For many women, tender breasts are an early sign of pregnancy. The breast completes its development during pregnancy, and milk production begins in the middle trimester. If a pregnancy ends after 15-16 weeks, colostrum (early milk) will be present. Some women choose to express colostrum in the last few weeks of pregnancy. This is recommended for women with diabetes, whose milk may be a bit slower to increase and whose babies may have low blood sugar after birth.Colostrum expressed before birth can be stored, to be given to the baby if they need extra milk. Mothers with high-risk pregnancies, or who are concerned about having enough milk, may also choose to express colostrum in the last weeks of pregnancy. It is usually recommended not to start before 36 weeks, unless premature birth is imminent. The amount of colostrum you can express before birth does not predict your ability to make enough milk afterwards.
After birth (day 1-3)– lactation takes off!
During pregnancy, milk production is held in check by the hormone progesterone, produced by the placenta. Once the baby is born and the placenta is delivered, levels of progesterone drop rapidly; this, coupled with high levels of prolactin, allows lactation to begin fully.
Retained placental fragments can reduce or even stop milk production. If you have unexplained low milk production and are still bleeding heavily or irregularly after you would expect to have stopped, check with your midwifery team or doctor. Removal of the last fragments of placenta will usually allow milk production to resume normally.
Mothers typically start to notice the signs of “onset of copious milk production” (also known as milk “coming in”) two or three days after birth. For a day or two you might experience:
Breast tenderness
Warmth
Discomfort
Swelling
Increase in breast size
Mild fever
The discomfort you feel is primarily due to tissue swelling, in response to the sudden increase in milk volumes. Don't panic – your breasts won't feel like this for long! As your breasts adjust to making the amount of milk your baby needs, the swelling will settle down. If feeding your baby or expressing milk doesn't quickly help you feel more comfortable, there are other steps you can take to deal with engorgement.
Onset of copious milk production can happen a bit more slowly:
For first-time mothers
After a more difficult birth
You may have read that being overweight or obese (having a higher BMI, especially over 30) can lead to breastfeeding problems. It is not clear whether having a higher BMI, by itself, is a problem for breastfeeding and many women with high BMI breastfeed easily. We do know that some conditions associated with higher BMI, such as diabetes and metabolic syndrome, may delay your milk “coming in” (increasing in volume) in the early days after birth. This can make breastfeeding more challenging.
To make milk, remove milk (day 3-4 onwards)
Until day 3-4, milk production is controlled entirely by hormones and will happen automatically, whether or not you go on to breastfeed. After day 3-4, another mechanism comes into play. Milk will only continue to be made if milk is removed from the breasts. The more milk that is removed, the more milk will be made. This enables your body to adapt to the number of babies you have. With enough milk removal, it is possible to exclusively breastfeed twins or triplets! If you do not breastfeed or express milk at all, your milk production will shut down within about two weeks after birth.
Remove milk early
The amount of milk that is removed in the period immediately after birth is important for later milk production. Research on lactation after premature birth has shown that starting to express milk within an hour of birth, compared with starting at six hours, is associated with more milk six weeks later.
If your baby has any risk factors for not being able to feed effectively at first, such as being:
Premature
Small for gestational age
Unwell
Jaundiced
Sleepy
Separated from you
then early, frequent milk expression will help to ensure plenty of milk to meet their needs, now and later. You can see a useful video about this at https: //med.stanford.edu/newborns/professional-education/breastfeeding/breastfeeding-in-the-first-hour.html OR click on "Read More" at the leftmost bottom of the article.
Parents who have risk factors for low milk supplycan give their milk production the best possible start by removing milk early and frequently after birth.
Risk factors include:
Previous history of low milk production
Previous breast radiation or surgery
Polycystic ovary syndrome (PCOS)
Thyroid problems (hypo- or hyper-)
A history of infertility with hormonal cause
Unevenly sized, widely spaced breasts, with little or no changes during or after pregnancy
Obesity (BMI over 30)
People with these risk factors may be able to make a full or partial milk supply – you never know what you can do until you try! If you are not producing all the milk your baby needs, you can still enjoy a close, happy feeding relationship with your baby. You can read more about how to use donor breastmilk or formula milk to support breastfeedinghttps://www.laleche.org.uk/formula-supplements/.
Some mothers who need to supplement their own supply with donor milk or formula milk in the early months are able to reduce or eliminate the supplementary milk after their baby starts complementary foods, at around six months, going on to happily breastfeed alongside solids.
Remove milk often
After their first feed and a few hours of sleep, full-term, healthy newborn babies feed frequently, around the clock. Most babies need to feed at least 8-12 times in 24 hours in the early weeks, suckling and swallowing actively at each feed, to get enough milk and stimulate their mother's milk production. If your baby is not feeding as often or energetically as this yet, it is important to express your milk, if your goal is a full milk supply.
As milk builds up in the breast, a protein in the milk, known as the “Feedback Inhibitor of Lactation” (FIL), begins to slow down milk production. Breasts that are full make milk slowly, and eventually not at all. Breasts that are well drained make milk quickly. This is why, if you are trying to maximize milk production, it is important not to wait until your breasts feel full before feeding or expressing. Over time, this will reduce milk production.
Different breasts, different feeding patterns
Storage capacityis quite a new concept in breastfeeding, and it explains a lot of things that mothers instinctively knew, but were not in the textbooks!
A mother's storage capacity is the amount of milk that her breasts can holdbetween feeds.It is notrelated to breast size and it is notrelated to the total amount of milk that a mother can make each day.
To understand storage capacity, let's assume that:
Alisha and Beth both have 3 month old babies and well established milk supplies.
Alisha’s breasts can hold 75ml of milk and Beth’s breasts can hold 150ml of milk.
Both their babies need about 750ml of milk per day (this is an average amount. Some babies might take as much as 1200ml per day).
Alisha’s baby needs to feed at least 10 times in 24 hours to get this amount of milk, while Beth’s baby could get the same amount of milk in only five or six feeds. [Feeding this infrequently is not common – it is at one end of a wide spectrum of feeding patterns!]
Both babies are getting as much milk as they need and growing well, but they have very different feeding patterns. What happens if Alisha and Beth are told that their babies “should” both be feeding eight times in 24 hours?
Alisha’s baby is hungry and miserable. She is no longer getting enough milk and if this continues, Alisha’s milk production will slow down due to the action of FIL in the full breast. It might be hard to increase milk production again, after the early weeks, when milk supply settles at a stable level.
Beth’s baby is irritable because his mother keeps trying to feed him again when he doesn’t want any more milk!
Both Alisha and Beth can successfully breastfeed their babies as long as their feeding pattern works for their milk storage capacity.
Beth, with her larger storage capacity, has more flexibility in her feeding patterns. Her baby is likely to have fewer feeds per day than Alisha’s, is more likely only to take one breast per feed and may start sleeping for longer stretches earlier. She could choose to feed more often, if her baby wanted to.
Alisha has less flexibility in her feeding patterns because if she doesn’t feed often enough, her breasts fill up and she doesn’t have room to make more milk. Her baby is likely to feed frequently day and night during the exclusive breastfeeding period and may need to feed on both breasts at most feeds.
Most babies need to feed at least 8-12 times in 24 hours and it is important to ensure frequent feeding during the early weeks, when milk production is becoming established. After the early weeks, most babies spend less total time feeding, as efficiency improves. Some babies will also significantly reduce the frequency of feeds.
Most mothers never need to worry or even think about their breast storage capacity, because their babies are brilliant at working it out for them! Full-term, healthy, thriving babies are able to choose their own feeding pattern that works with their mother's breasts and their own needs as they grow. If your baby is growing well and seems contented, their feeding pattern is working well for them.
Fat in milk
This is a topic that often worries parents, because of poorly understood information circulating among families about the differences between “foremilk” and “hindmilk”.
We know from research that:
The breast makes milk fat at a stable level. The types of fat in milk are somewhat related to the types of fat in the mother's diet, but the amount of fat is not related to her diet.
The milk available at the start of a feed (often referred to as foremilk) has a lower level of fat than the milk at the end of the feed (often referred to as hindmilk). As the breast is drained, fat levels in milk increase as more fat droplets are “squeezed” to the front of the breast and out through the nipple.
The level of the fat at the start of one feed depends on how long it has been since the last feed. The longer the interval between feeds, the lower the level of fat at the start of the next feed.
Parents often worry, or are told, that their baby might not get enough fat (this is often described as “getting too much foremilk”)
Research shows that full-term, healthy, thriving babies are brilliant at balancing their own diets. They will stop feeding when they have had enough calories. When fat levels in milk are higher, they will take less milk. When fat levels are lower, they will take more. The varying amount of fat in milk is not a problem – all the milk is good! It enables babies to quench their thirst at the start of a feed and finish with a creamy “dessert”, if they want to.
The balance of fat in milk can be a problem for a small number of babies, if:
The baby is taken off the breast before they have had as much milk as they wanted; or
There is an overwhelming amount of milk. In this case, the baby may be growing very fast (their growth curve crosses percentiles upwards on the growth chart) and may struggle with the speed of milk flow, coming off the breast gagging, spluttering and upset. You can find practical tips to help your baby manage fast milk flow https://www.laleche.org.uk/too-much-milk-and-oversupply/.
In either of these two situations, the baby may not get enough fat to slow down the transit of milk through their gut. Milk may rush through the gut faster than the baby can digest the milk sugar (lactose). The sugar ferments in the gut, producing green, frothy, explosive poo, flatulence (farting) and severe discomfort.
A baby who does yellow poo and is comfortable does not have any problem with the balance of fat in their diet. A baby who is growing more slowly than expected needs more milk overall, not just more fat. These babies should be seen by a doctor to rule out an underlying health problem.
You can read more about fat levels in milk https://www.laleche.org.uk/health-professionals/fat-content-breastmilk-faqs/.
How much milk?
In the first 24 hours after birth, volumes of colostrum are small, but enough for your baby. The average amount per feed is about 7ml (1 ½ teaspoons). This is because full-term babies are not hungry – they are born with food stores in their body. They don't need fluid – they shed extra fluid in the first few days (this is why most babies lose a little weight). Colostrum is primarily immune protection, rather than food. It coats the inside of the baby's gut to keep pathogens out, stimulates the baby's immune system, and provides the baby with a powerful, tailor-made dose of growth factors, hormones, live immune cells and other components that no manufactured milk can begin to match.
The small quantity and thick texture of colostrum give the baby a chance to practice feeding before they have to manage larger volumes. The amount of colostrum increases quickly, more or less doubling every day in the first few days. If you need to express on the first day after birth, you might use a syringe to catch drops. A syringe quickly becomes too small for the increasing volumes. By the 5thday after birth a baby might be taking 60ml (2oz) or more per feed.
If you are expressing your milk, for example because your baby was born early, it can help to know how much to aim for:
500ml in 24 hours by the end of the first week after birth
750ml in 24 hours by the end of the second or third week after birth
Your baby might not need this much milk yet, but aiming for a full supply now means you will have enough to satisfy them for the rest of their breastfeeding time.
Milk production remains stable, within a range of about 600ml – 1200ml per 24 hours, from about one month after birth to six months. After the baby starts eating complementary foods, milk production starts to decrease, as milk is gradually replaced by other foods in the baby's diet. If you are making as much milk as your baby needs at one month, you are likely to keep on doing so, as long as your baby keeps on removing enough milk and you don't get pregnant or use one of a small number of medications that can affect milk production. Birth control methods that contain progesterone may reduce milk production in some women.
How milk changes
If you are expressing your milk, you will be able to see the change from sticky, transparent, yellow or orange colostrum to thinner, white or blue-ish “transitional milk” by about the fourth day after birth. The composition of your milk is changing to adapt to your baby's need for more energy. Your milk changes from day to day for as long as you breastfeed or express, responding to your baby's stage of development, any illnesses you or your baby are in contact with, and even the time of day or night it was made.The milk of mothers who give birth prematurely is initially different from the milk of mothers who give birth at full term, to meet the extra needs of their babies.
Getting back on track after a difficult start
Milk production peaks by about a month after birth, with most of the increase happening in the first two weeks. Many mothers find it becomes more difficult – in some cases impossible – to increase the amount of milk they are making, after the early weeks. This is why it is important to get good feeding support early, if there are any signs that there might be a problem with your baby getting enough milk, for example, if your baby:
Does not poo every day (in the first 4-6 weeks)
Has pink crystals (urates) in their nappy after the third day
Is not doing yellow poo by the end of the fourth day
Loses more than 7% of their birth weight by the fifth day
Loses weight after the fifth day
Does not regain their birth weight by 10-14 days
An LLL Leader or infant feeding specialist can help you work out whether there is likely to be a problem with milk production or whether (more commonly) your baby is not yet feeding effectively. If not enough milk is being removed, the risk is that your milk production will not increase to the level your baby needs. Expressing your milk gives you time to work on any feeding issues.
If the problem is with milk production, your breastfeeding supporter can help you make a plan to keep your baby safely fed while you work tomaximise your milk supply. You will need to work closely with your baby's healthcare providers to monitor their growth and well-being.
Lactation beyond the early months
Parents are sometimes told that their milk has no value to their baby after 6 months, or 12 months. This is not the case.Milk is the baby's main source of protein and calories until about a year of age, and continues to contribute to the child's health and nutrition through the second year and beyond.
Your milk adapts to meet your baby's needs as they grow. For example:
From about six months, the digestive enzyme amylase starts to be present in milk, helping your baby digest starchy foods.
From about six months, levels of the antibacterial enzyme lysozyme increase in milk, protecting your baby as they put foods and other objects in their mouth.
As the total amount of milk begins to decrease gradually, from about six months, levels of key immune factors such as immunoglobulins increase, so that the child receives about the same amount per day, even though they take less milk.
Levels of fat, protein and energy in milk are higher in the second year than in the first year of lactation.
Lactation ends – involution
Milk will continue to be made in the breast for as long as milk is removed from the breast. In the early days of lactation, milk supply is relatively fragile – the mother's body quickly shuts down production if milk removal stops. In later lactation, milk production is much more robust. Mothers returning to work after six months, for example, can be confident that their milk supply will withstand variations in their schedule from day to day and week to week. In later lactation it is possible to breastfeed part-time, even if you work shifts or need to travel away overnight. Many breastfeeding toddlers and older children spend time away overnight with a non-resident parent, grandparents, etc. and continue breastfeeding when they are with their mother.
It takes at least 40 days for the breast to reach complete “involution” (a non-lactating state) after the end of breastfeeding or milk expression. Some mothers find that they leak or can express drops of milk months or even years after their last feed. If the amount of milk is large, or you start making milk again after a gap even though you are not pregnant, check with your doctor. Spontaneous milk secretion (galactorrhoea) can be a side effect of some medications, or a sign of hormonal dysfunction.
When children are able to wean from the breast at their own pace, weaning often takes place over a period of months and years. The most common time for children to choose to stop breastfeeding is between their second and third birthdays.Milk production reduces gradually and, by the time the child has their final feed, may have dwindled to almost nothing. Some of the immune components of milk become more concentrated as milk volumes decrease, so the child continues to benefit to the last drop of breastmilk.
Written by Jayne Joyce, LLL Oxfordshire and Karla Napier, LLL Edinburgh – February 2021
References:
1Forster, D.A. et al. Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomised controlled trial.Lancet,2017; 389 (10085): 2204-2213. Available at https://pubmed.ncbi.nlm.nih.gov/28589894/(accessed 20 February 2021).
2Parker, L.A. et al. Association of timing of initiation of breastmilk expression on milk volume and timing of lactogenesis stage II among mothers of very low-birth-weight infants. Breastfeeding Medicine, 2015; 10 (2): 84-91. Available at https://pubmed.ncbi.nlm.nih.gov/25659030/(accessed 20 February 2021).
3Kent, J.C. et al. Volume and Frequency of Breastfeedings and Fat Content of Breast Milk Throughout the Day. Pediatrics, 2006; 117 (3): e387-e395. Available at https://pediatrics.aappublications.org/content/117/3/e387(accessed 20 February 2021).
4Academy of Breastfeeding Medicine. ABM Clinical Protocol #13: Contraception During Breastfeeding, Revised 2015. Breastfeeding Medicine, 2015; 10 (1). Available at https://abm.memberclicks.net/assets/DOCUMENTS/PROTOCOLS/13-contraception-and-breastfeeding-protocol-english.pdf(accessed 21 February 2021).
5Italianer, M.F. et al. Circadian Variation in Human Milk Composition, a Systematic Review. Nutrients, 2020; 12 (8): 2328. Available at https://pubmed.ncbi.nlm.nih.gov/32759654/(accessed 21 February 2021).
6Perrin, M.T. et al. A longitudinal study of human milk composition in the second year postpartum: implications for human milk banking. Matern Child Nutr, 2017; 13 (1): e12239. Available at https://pubmed.ncbi.nlm.nih.gov/26776058/(accessed 21 February 2021).
7Sinkiewicz-Darol, E. Tandem Breastfeeding: A Deive Analysis of the Nutritional Value of Milk When Feeding a Younger and Older Child. Nutrients, 2021; 13 (1): 277. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835967/(accessed 21 February 2021).
8Dettwyler, K.A. A Natural Age of Weaning. 1999. https://www.researchgate.net/publication/265185534_A_Natural_Age_of_Weaning(accessed 21 February 2021).
作者:杰妮乔伊斯，国际母乳会牛津郡分会和卡拉纳皮尔，国际母乳会爱丁堡分会 ——2021年2月
资料来源：
How milk production works - La Leche League GB
https://www.laleche.org.uk/how-milk-production-works/
END
文章：杰妮乔伊斯、卡拉纳皮尔
翻译：传艳
审核：Lynn、Marien、Victoria
编辑：沐凡
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