According to the Egyptians,

埃及人的方法是，

all you have to do is urinate on wheat and barley seeds, and wait.

你只要分別在小麥和大麥種子上排尿，之後就是等待。

If either sprouts, congratulations, you're pregnant!

如果兩者之中有一個發芽了，那麼恭喜，妳懷孕了！

And if wheat sprouts faster, it's a girl, but if barley, it's a boy.

如果小麥發芽的早，那就是個女孩；如果是大麥先，那就是個男孩。

In 1963, a small study reproduced this test

在 1963 年，有個小研究再現了這個驗孕方式，

and found that it predicted pregnancy with a respectable 70% accuracy,

他們發現，這種方法的精準度有相當可敬的 70%。

though it couldn't reliably tell the sex of the baby.

儘管它並無法準確地分析嬰兒的性別。

Scientists hypothesized that the test worked

科學家推測這個方式會成功，

because pregnant women's urine contains more estrogen, which can promote seed growth.

是因為孕婦的尿液中含有較多的雌激素，而它可以促進種子的生長。

Now it's easy to take this ancient method for granted

如今，我們都認為這個古老的方法是理所當然地有效，

because modern pregnancy tests give highly accurate results within minutes.

因為現代的驗孕方式在幾分鐘之內就有高準確度的結果。

So how do they work?

那麼現在是怎麼驗孕的呢？

Over-the-counter pregnancy tests are all designed to detect one thing: a hormone called HCG.

非處方式的驗孕方式都是為了偵測一個東西而設計，也就是絨毛膜激素。

HCG is produced in the earliest stages of pregnancy

絨毛膜激素會在懷孕最初期產生，

and starts a game of telephone that tells the body not to shed the inner lining of the uterus that month.

並且會以傳聲筒的方式告訴身體，在當月份不要使子宮內膜脫落。

As the pregnancy progresses, HCG supports the formation of the placenta,

懷孕到中後期，絨毛膜激素則會協助胎盤形成，

which transfers nutrients from mother to fetus.

它負責將母親的養分傳送給胚胎。

The test starts when urine is applied to the exposed end of the strip.

驗孕測試從尿液接觸到驗孕棒裸露的一端開始。

As the fluid travels up the absorbent fibers,

在尿液穿過這些吸水纖維的過程中，

it will cross three separate zones, each with an important task.

它會分別經過三個不同的區域，每個都有一項重要的使命。

When the wave hits the first zone, the reaction zone,

當液體抵達第一區，也就是「反應區」時，

Y-shaped proteins called antibodies will grab onto any HCG.

稱之為抗體的 Y 型的蛋白會抓住任何絨毛膜激素。

Attached to these antibodies is a handy enzyme with the ability to turn on dye molecules,

附著在這些抗體上的，是一種可以觸發染色分子的酵素，

which will be crucial later down the road.

他們在後面的過程中會產生重要的影響。

Then the urine picks up all the AB1 enzymes and carries them to the test zone, which is where the results show up.

接下來，尿液會帶著所有第一區的抗體到測試區，也就是顯示結果的地方。

Secured to this zone are more Y-shaped antibodies that will also stick to HCG on one of its five binding sites.

在這一區有更多的 Y 型抗體，他們同樣會附著在絨毛膜激素五個中的一個結合位上。

Scientists call this type of test a sandwich assay.

科學家稱這樣的形式為「三明治型態」。

If HCG is present, it gets sandwiched between the AB1 enzyme and AB2,

如果有絨毛膜激素存在，它就會被一號抗體酶與二號抗體像三明治一樣夾起來，

and sticks to the test zone, allowing the attached dye-activating enzyme to do its job and create a visible pattern.

這樣的組合會附著在測試區，並且讓能誘發染色酶的激素上工，產生一個可見的圖案。

If there's no HCG, the wave of urine and enzymes just passes on by.

如果沒有絨毛膜激素，尿液和酵素就只是路過，不會起任何反應。

Finally, there's one last stop to make, the control zone.

最後，只剩下最後一個階段，也就是控制區。

As in any good experiment, this step confirms that the test is working properly.

就像所有好的實驗一樣，這個階段是用來測試檢驗是否正常運作。

Whether the AB1 enzymes never saw HCG,

不論是第一區的抗體沒有偵測到絨毛膜激素，

or they're extras because Zone 1 is overstocked with them,

或這些抗體其實是多餘的，因為第一區已經被他們的同伴占滿了，

all the unbound AB1 enzymes picked up in Zone 1 should end up here and activate more dye.

所有在第一區落單的抗體都會到這裡來，並且啟動觸發更多染色程序。

So if no pattern appears, that indicates that the test was faulty.

所以，如果沒有圖案顯示，代表這個檢設可能是無效的。

These tests are pretty reliable, but they're not failproof.

這些測試結果相當可靠，但他們並不是百分之百正確無誤。

For instance, false negatives can occur if concentrations of HCG aren't high enough for detection.

例如，漏報的情況可能發生在絨毛膜激素的濃度不夠高，以至於無法檢測出來。

After implantation, HCG levels double every two to three days, so it may just be too early to tell.

在著床之後，絨毛膜激素的濃度每兩到三天會倍增，所以可能只是檢驗得太早了。

And beverages can dilute the urine sample,

此外，飲料會稀釋尿液樣本，

which is why doctors recommend taking the test first thing in the morning.

這就是為什麼醫生會建議，驗孕測試應該一早起來就要進行。

On the other hand, false positives can come from other sources of HCG,

另一方面，其他絨毛膜激素的來源可能導致誤報，

like IVF injections, ectopic pregnancies,

例如試管嬰兒注射、子宮外孕，

or certain cancers such as uterine cancer or testicular cancer,

或像子宮癌或睪丸癌等特定的癌症，

making it possible for one of these tests to tell a man he's pregnant.

可能會讓一個男人檢驗出他懷孕了的消息。

The best way for a woman to find out for sure is at the doctor's office.

對女人來說，確認是否懷孕的最好方法，就是親自到醫生那裏去一趟。

The doctors are also looking for HCG,

醫生們的方法，也是要尋找絨毛膜激素，

but with tests that are more sensitive and quantitative,

但他們會使用更敏銳且更量化的方式進行測量，

which means they can determine the exact level of HCG in your blood.

也就是說，他們可以計算出你血液中絨毛膜激素的確切濃度。

A few minutes can feel like forever when you're waiting on the results of a pregnancy test.

當你在等待驗孕的結果時，短短的幾分鐘感覺起來就像一輩子一樣漫長。

But in that brief time, you're witnessing the power of the scientific method.

但在那短暫的時間裡，你見證了科學方法的威力。

That one little stick lets you ask a question,

這一根小小的棒子讓你問了一個問題、

perform a controlled experiment,

呈現出一個精準的實驗，

and then analyze the results to check your original hypothesis.

並讓你藉由分析成果來驗證自己的假說。

And the best part is you won't even have to wait until the next harvest.

最棒的部分是，你不需要等到下次的豐收季！