Sitting next to a breastfeeding mother on a flight to theUSlast week, I'll admit to feeling slightly queasy. I know thatbreastfeedingis one of the most natural things in the world and I hope to be able to feed my daughter this way, but I'm afraid the way babies suck on the nipple does put me in mind of a dairymaid milking acow – and I can't help worrying that it is going to hurt.
上周飞往美国途中，紧挨着一名正在哺乳的母亲坐着，我得承认我有轻微的呕吐感。虽然我清楚哺乳是这个世界上最自然的事情之一，而且希望自己也能亲自给女儿哺乳，但我还是害怕婴儿吮吸乳头的这种方式，这让我想起奶牛场女工给母牛挤奶的情形——而且，我还忍不住担心那会让我感觉疼痛。
However,research presented at the Medela breastfeeding and lactating symposium in Venice, Italy, last weekendsuggests that I may have got it all wrong. Although it might look like a baby is chewing on the mother's nipple, ultrasound images show that the infant actually removes milk by creating a vacuum – also known as sucking.
不过，上周末意大利威尼斯举办的美怡乐母乳哺育与授乳妇女座谈会所介绍的研究让我想到，一直以来我可能都错了。虽然哺乳可能看起来很像婴儿在咀嚼妈妈的乳头，可超声波影像显示婴儿实际上是通过创造一个真空——也被认为是吮吸的方式来使奶水流动。
The finding is important, as it could explain whysome babies fail to take to the breast. It may also shed new light on why – for a minority of women – breastfeeding really can be a painful experience.
这一发现很重要，因为它可以解释为什么有的婴儿不能吸到母乳的原因。它还对为什么——对少部分妇女来说——哺乳真的能成为一种痛苦体验的原因作了进一步的阐述。
Squeeze or suck?
挤还是吸？
"There have been two theories about how breast milk is expressed," saysDonna Geddes(no relation) of theUniversity of Western Australia in Crawley.
“关于乳汁怎样被挤出，存在两种理论，”克劳利西澳大利亚大学的Donna Geddes（并非亲属）说。
"One is that the baby uses a peristaltic or compression motion to actually push the milk out of the nipple and breast. The other theory is that vacuum is primary in removing the milk."
“一种理论认为婴儿使用蠕动或挤压的动作使奶水真正挤出乳头和乳房。另一种理论认为在奶水的流动中真空才是主要原因。”
Until now, most studies examining the mechanics of breastfeeding have focused on bottle-feeding infants, or on old X-rays that were of poor quality.
迄今为止，大部分哺育机制原理调查研究多集中在用奶瓶喂养的婴儿身上或者是用过时的、品质不佳的X-射线来进行调查。
Instead, Geddes and her colleagues combined ultrasound imaging of infants suckling on the breast with measurements of the strength of the vacuum created by the baby's mouth in 20 infants aged 3 to 24 weeks as they breastfed (see video).
与之相反，Geddes及其同事将20个3-24周婴儿吃奶（见视频）时吸吮乳房的超声波影像与该婴儿口腔所形成的真空力度测量结果结合起来作研究。
"What we see is that when the tongue is lowered and the vacuum is applied, that's when the milk is coming out of the breast, and that doesn't involve any compression of the nipple," says Geddes."It's not a milking action at all."
“我们看到的是，当舌头位置较低时，真空就能用上，也就是奶水从乳房流出的时侯，而且这不会引起对乳头的任何挤压，”Geddes说。“那根本就不是一个挤奶动作。”
Feeding failures
哺乳障碍
They also found that infants who struggled to breastfeed generated much weaker vacuums than successful breastfeeders. This may explain why babies with a cleft palate often fail to breastfeed, as do premature babies: preterm infants don't have strong enough mouth muscles to suck hard enough.
他们还发现，那些不能吸食母乳的婴儿比能成功吸食母乳的婴儿产生的真空要弱得多。这点可以说明为什么腭裂婴儿不能吸食到母乳的原因，早产儿也是这样：早产婴儿没有足够有力的口腔肌肉来用劲吮吸。
The next step is to devise a simple and universal test that could be used to assess babies' ability to suck. This could reassure mothers whose infants are struggling to feed that it's not their fault."Currently there are no measurements to assure the mother or the clinician that things [in the breast] are working," says Geddes.
下一步就是设计一个简单又通用的、可用来评估婴儿吮吸能力的测试方法。这可以消除其小孩不能成功吸食母乳的母亲们的疑虑，那不是她们的过错。Geddes 认为，“现在还没有可以让母亲或临床医生确信乳房内物质流动的测量方法。”
For such women, keeping the milk flowing using a breast pump and using this to top up breastfeeding until the baby is strong enough to suck effectively may be a better option than giving up on breastfeedingaltogether.
对这些妇女来说，利用吸乳器让奶水持续流出并用其装满抽出的乳汁直至婴儿强壮到足以有力吮吸为止，也许是一个总体上来说比放弃母乳喂养更好的选择。
When it's a pain
乳房疼痛时
The team also looked at women who found breastfeeding painful and discovered that their infants had a particularly vigorous action.
该研究团队还对发现哺乳疼痛的妇女进行观察，他们发现，她们的小孩动作特别有力。
"They're strong suckers," says Geddes. Somewere also distorting or crushing the nipple. Further study of these infants may aid the development of better nipple shields to reduce pain during breastfeeding.
Geddes说，“他们吮吸很有力。”有些还会使乳头扭曲或变形。对这些婴儿作进一步研究可能有助于可减少哺乳期疼痛的乳头保护套的研发。
These finding haven't completely allayed my fears about breastfeeding, but it's nice to feel a little less like a dairy cow intraining.
这些发现并没完全消除我对哺乳的恐惧，但它淡化了哺乳的母亲就像一头驯养奶牛一般的感觉，这就很好。
