The surprising effects of pregnancy

譯者: C Cheng 審譯者: Helen Chang

Muscles and joints shift and jostle.

肌肉與關節發生移位和擠壓。

The heart’s pounding rhythm speeds up. Blood roars through arteries and veins.

心跳節奏加快。

血液在動脈和靜脈中轟鳴。

Over the course of a pregnancy, every organ in the body changes.

在妊娠過程中， 體內的每個器官都發生變化。

Ignited by a range of hormones,

這些變化由一系列激素引發，

these changes begin as soon as pregnancy begins.

在妊娠一開始時便出現了。

Just days after fertilization, the embryo implants in the lining of the uterus.

在受精後的幾天內， 胚胎就會被植入子宮內膜。

Because its DNA doesn’t exactly match the mother’s,

因為它的 DNA 與 母親的 DNA 不完全匹配，

the immune system should theoretically recognize it as an invader,

所以，理論上講，免疫系統 會將它視為一個入侵者，

attack, and destroy it, like it would bacteria or other harmful microbes.

從而對其實施攻擊和摧毀，就如同 對待細菌和其他的有害微生物一樣。

That’s the challenge: the mother’s immune system

這是一個挑戰：母親的免疫系統

needs to protect both her and the fetus, but can’t act as it usually does.

需要同時保護自身和胎兒， 但又不能像通常那樣運作。

What happens is not as simple as decreasing the immune response.

事情並不像降低 免疫反應那麼簡單。

Instead, it’s a complex interaction we’re just beginning to understand,

相反，這是一個複雜的相互作用， 我們對此也才剛剛有所了解。

involving many different types of immune cells—

它涉及許多不同類型的免疫細胞——

some of which seem to protect the fetus from attack by other immune cells.

其中一些細胞似乎在保護胎兒 免受其他免疫細胞的攻擊。

The body also creates an antibacterial plug made of mucus on the cervix,

人體還在子宮頸上製造了 一個由粘液構成的抗菌栓，

which keeps germs away and stays sealed until labor.

它可以防止細菌入侵 並保持密封直至分娩。

As a pregnancy progresses,

隨著妊娠的推進，

the uterus expands upward and outward with the growing fetus.

子宮會隨著胎兒的生長 而向上和向外膨脹。

To make room, hormones called progesterone and relaxin

為了騰出空間，兩種被稱為 孕酮和鬆弛素的激素

signal muscles to loosen.

會向肌肉發出放鬆的信號。

The muscles that propel food and waste through the digestive tract also loosen,

那些在消化道內推動食物 和排泄物的肌肉也會變得鬆弛。

which makes them sluggish,

這就使肌肉運動變得遲緩，

causing constipation as passage through the tract slows down.

從而造成便秘，因為其通過 消化道的速度放慢了。

Loosened muscles at the top of the stomach

胃部上方鬆弛的肌肉

might allow acid to escape into the esophagus and throat,

可能會使胃酸逸入食道和咽喉，

causing heartburn and reflux.

引起胃灼熱和逆流。

These changes can worsen morning sickness,

這些變化會加劇晨間孕吐。

which is caused in part by hormone HCG— and can also happen at other times of day.

它部分是由 HCG 激素引起的—— 也可能發生在一天中的其他時間。

As the uterus grows, it pushes on the diaphragm,

隨著生長，子宮會擠壓橫膈膜；

the muscle that expands and contracts the chest with each breath.

橫膈膜是每次呼吸時 控制胸腔擴張和收縮的肌肉。

This limits the diaphragm’s range.

這就限制了橫隔膜的運動範圍。

To compensate, the hormone progesterone acts as a respiratory stimulant,

作為彌補，黃體酮激素發揮了 呼吸興奮劑的作用，

making the pregnant woman breathe faster so both she and the baby

它使孕婦呼吸加快，以便讓她和胎兒

can both get enough oxygen with less lung capacity.

在肺活量減小的情況下 都可以得到足夠的氧氣。

This all may leave the pregnant woman feeling short of breath.

這都可能使孕婦感到喘不過氣。

Meanwhile, the kidneys make more erythropoietin,

同時，腎臟製造出 更多的紅血球生成素，

a hormone that increases red blood cell production.

一種提高紅細胞生成的激素。

The kidneys also keep extra water and salt rather than filtering it out into urine

腎臟還把額外的水和鹽分儲存了 起來，而不是將其過濾到尿液中

to build up the volume of the blood.

以此來增加血液容量。

A pregnant woman’s blood volume increases by 50% or more.

孕婦的血液容量會增加 50％ 以上。

But it’s also a bit diluted,

但血液也被稍微稀釋了，

because it only has 25% more red blood cells.

因為它的紅細胞只增多了 25％。

Usually, the body makes blood cells using iron from our food.

通常，人體利用食物中的 鐵元素製造血細胞。

But during pregnancy, the fetus is also building its own blood supply

但是在懷孕期間，胎兒也在 建立自己的血液供應，

from nutrients in the mother’s food—

從母親的食物中吸收營養成分——

leaving less iron and other nutrients for the mother.

從而減少了母親體內的 鐵和其他營養成分。

The heart has to work extra hard to pump all this blood

心臟必須格外用力

才能把血液泵送到全身和胎盤。

through the body and placenta.

A pregnant woman’s heart rate increases,

孕婦的心率會增加，

but we don’t fully understand how blood pressure changes in a healthy pregnancy—

但我們還不完全了解 血壓在健康妊娠內如何變化——

an important area of research,

這是一個重要的研究領域，

because some of the most serious complications

因為一些最為嚴重的併發症

are related to the heart and blood pressure.

與心臟和血壓有關。

The expanding uterus may press on veins—

擴張中的子宮會壓迫靜脈——

causing fluid buildup in the legs and feet.

造成下肢水腫。

If it presses on a large vein called the inferior vena cava,

如果壓迫在被稱為 下腔靜脈的大靜脈上，

it might interfere with blood returning to the heart,

它可能會干擾到血液回流到心臟，

causing a dizzying drop in blood pressure after standing for too long.

站立過久後，會造成血壓下降， 令人感到眩暈。

Some of these changes start to reverse even before birth.

其中一些變化甚至 在嬰兒出生前就開始發生逆轉。

Shortly before delivery, the fetus drops down,

分娩前夕，胎兒下落，

decreasing the pressure on the diaphragm

從而減輕了對橫膈膜的壓力，

and allowing the pregnant woman to take deeper breaths.

使孕婦能夠進行深呼吸。

During labor and birth,

在分娩期間，

much of the extra fluid in the body is lost when the water breaks.

體內的大量積水 會因羊水破裂而流失。

The uterus shrinks back down in the weeks after birth.

子宮會在分娩後的幾週內收縮。

Like the rest of the body, pregnancy affects the brain—

像身體的其他部分一樣， 妊娠會影響到大腦——

but its effects here are some of the least understood.

但是我們對此處的影響卻知之甚少。

Recent studies show differences in brain scans

最新研究顯示，

在妊娠後及早期育兒階段 存在著大腦掃描上的差異，

after pregnancy and early parenting,

and suggest that these changes are adaptive.

表明這些變化是適應性的，

That means they could help with parenting skills,

可能有助於提升育兒技巧，

such as an increased ability to read facial cues since babies can’t talk.

比如，由於嬰兒不會說話，對面部 表情的解讀能力因此而得到提高。

The lack of information about pregnancy’s effects on the brain

缺乏有關妊娠對大腦影響的信息

highlights a general truth: historically, almost all the research around pregnancy

突顯出一個普遍的事實： 幾乎所有歷來關於妊娠的研究

has focused on the fetus, rather than pregnant women.

針對的都是胎兒而非孕婦。

Experiences of pregnancy vary widely,

對妊娠的體驗存在著很大差異。

both within the range of healthy pregnancies

這既出現在健康妊娠範疇中，

and due to complicating health conditions— new research will help us understand why,

也由複雜的健康狀況引起。

新的研究將幫助我們了解其原因

and develop effective treatments where necessary.

並開發出必要和有效的治療方法。

In the meantime, every pregnancy is different,

同時，每次妊娠都不一樣，

and it’s important to consult a doctor with any specific questions.

因而向醫生諮詢任何具體問題 都是非常重要的。

Today, we’re turning an exciting corner,

如今我們正值振奮人心的轉角處，

as more research is devoted to the astounding biology of pregnancy.

針對妊娠中驚人的 生物現象的研究越來越多。