How do contraceptives work? - NWHunter

譯者: Helen Chang 審譯者: Ann Chen

Here's what has to happen for pregnancy to occur after sexual intercourse.

性交之後必須有下列情形才會懷孕

Sperm must swim up the vagina,

精子必須沿著陰道上行

through the cervical opening,

通過子宮頸口

upwards through the uterus,

向上通過子宮

and into one of the two fallopian tubes.

進入兩個輸卵管之一

If an egg, released during that month's ovulation, is in the tube,

如果該月釋出的卵子正好在輸卵管中

one sperm has a chance to fertilize it.

某一精子就有機會與卵子結合

Contraceptives are designed to prevent this process,

避孕用品是設計來不讓這過程發生

and they work in three basic ways.

依三種基本原理來作用

They block the sperm,

1. 阻隔精子

disable sperm before they reach the uterus,

2. 使精子在到達輸卵管前喪失能力

or suppress ovulation.

3. 抑制排卵

Block is the simplest.

阻隔是最簡單的方式

Male and female condoms prevent sperm from coming into contact

男用和女用保險套阻止精子接觸陰道

with the vaginal space.

That barrier is also why they, unlike other contraceptive methods,

與其它避孕方法不同的是

are able to prevent transmission of certain sexually transmitted diseases.

阻隔法也能避免傳播某些性病

Meanwhile, the diaphragm, cervical cap, and sponge

避孕隔膜、子宮帽和避孕海綿

work by being placed over the cervix, barricading the entrance to the uterus.

放在子宮頸上以阻礙精子進入子宮

These contraceptives are sometimes called barrier methods

這類避孕法有時被稱為 「障礙避孕法」

and can be used with spermicides,

能與殺精劑並用

an example of the second category, disable.

殺精劑是第二類 （使精子喪失能力）的一個實例

A spermicide is a chemical that immobilizes and destroys sperm.

殺精劑這種化學藥物 可使精子失去游動力和殺滅精子

Today's spermicides come as foam, cream, jelly, suppositories,

當前殺精劑的主要形式是 泡沫、乳液、凝膠、栓劑

and even a thin piece of translucent film that dissolves in the vagina.

甚至是會溶解於陰道內的半透明薄膜

These products can be inserted directly into the vagina before intercourse,

這些產品能在性交前直接被置入陰道

or can be combined with block methods, like a diaphragm or condom,

或與阻隔法合用 例如避孕隔膜或保險套

for added proection.

以增強避孕的效果

The third category for preventing pregnancy

第三類避孕法的原理是

works by suppressing the action of an egg maturing in the ovary.

抑制卵子在卵巢中的成熟進程

If there isn't an egg available in the fallopian tube,

如果輸卵管內没有成熟的卵子

there's nothing for sperm to fertilize.

就沒有卵子可受精

Hormonal contraceptives,

激素類避孕劑

including the pill, the patch, the Depo shot, and the vaginal ring

包括口服藥丸、避孕貼片、 避孕針和陰道環

all release synthetic versions of various combinations of progesterone and estrogen.

都會釋放各種合成的 黃體素和雌性素的混合物

This hormone cocktail suppresses ovulation,

這種激素類混合物會抑制排卵

keeping the immature egg safely sequestered in the ovary.

安全地隔絕卵巢中未成熟的卵子

Synthetic progesterone also has a block trick up its sleeve.

合成黃體素也具有阻隔的招數

It makes cervical mucus too thick and sticky for sperm to swim through easily.

它使子宮頸黏液變得粘稠 精子不易通過

There are other contraceptives that use multiple approaches at the same time.

也有其他的方式混用數種避孕的方法

For example, many IUDs, or intrauterine devices,

例如，許多子宮內避孕器

contain synthetic hormones which suppress ovulation.

含有抑制排卵的合成激素

Some also contain copper,

有些還含有銅

which disable sperm while also making egg implantation in the uterus difficult.

使精子喪失活力 並使卵子不易在子宮內著床

Block, disable, or suppress:

阻隔、使失去活力或者抑制

is one strategy better than the other?

其中的一種方法勝過其他方法嗎？

There are differences, but a lot of it has to do with how convenient

它們各有擅長，但主要取決於便利性

and easy it is to use each contraceptive correctly.

和能夠正確使用的容易程度

For example, male condoms would be about 98% effective

例如，男用保險套能達 98% 的效果

if everyone used them perfectly.

如果每個人都正確使用的話

That 98% means if 100 couples correctly used condoms for a year,

那 98% 的意思是在一年的期間裡 一百對伴侶正確地使用保險套

two women would get pregnant.

會有兩個女人懷孕

But not everyone uses them correctly, so they're only 82% effective in practice.

但是並非每個人都正確地使用 所以實際上的效果只有 82%

Other methods, like the patch and pill, are 99% effective

其它方法如避孕貼片、口服避孕藥

有 99% 的效果

when they're used perfectly.

如果被正確地使用的話

But in practice, that's 91%.

但是實際上只有 91%

Spermicide is only 85% effective, even with perfect usage,

而正確使用殺精劑的效果僅有 85%

and just 71% effective with typical usage.

一般的使用情形下只剩 71%

Another important consideration in the choice of contraceptives are side effects,

另一選擇避孕法的重要因素 是考量其副作用

which almost exclusively affect women rather than men.

受影響的幾乎全是女人，不是男人

Hormonal methods in particular can cause symptoms like headaches,

尤其激素類方法會引起一些症狀

例如頭疼、噁心以及高血壓

nausea,

and high blood pressure,

but they vary from woman to woman.

因人而異

That's why these methods require a prescription from a doctor.

這也是為何激素法需要醫生的處方

The choice of contraceptive method is a personal one,

避孕法取決於個人的選擇

and what works best for you now may change later.

現在適用你的方法可能以後不合用

Scientists also continue to research new methods,

科學家也持續地研究新方法

such as a male pill that would prevent sperm production.

例如阻止產生精子的男性避孕藥丸

In the meantime, there are quite a few options

於此其間，我們有數種選項：

to block sperm,

阻隔精子

disable them,

使精子失去活力

or suppress eggs and keep them out of reach.

或是抑制卵子，使精子無法接觸