这是从英国NHS（即英国医疗服务体系）的网站上看到的。看了以后觉得对自己非常有帮助。这段时间备孕泡论坛看到许多姐妹一遍一遍地测ZZY，PLSZ，自己也忍不住用排卵试纸测了一次，测了个大白板，心情非常跌宕起伏。离测ZZY的日子还差几天，用PLSZ测又感觉好像是不尊重科学。。。难道等待开奖的日子就应该这么难熬吗？ 有多少心情起伏的成分是我们人为造成的呢。NHS作为英国的全民医疗服务体系，发表的东西是比较可信的。所以特别希望把来自于NHS这样比较权威渠道的指导和坛子里的姐妹们分享。急于知道答案的心情人人都有，可我们也许真的不必那么着急。原文地址：http://www.nhs.uk/chq/pages/948.aspx 网站上还有更多的专业指导。
How soon can I do a pregnancy test?
我什么时候可以开始早孕测试？
You can do a pregnancy test from the firstday of your missed period.
你可以在经期错过的第一天开始早孕测试。
If you have regular periods, you’llprobably know when this is.
如果你有规律的月经周期的话，你应该知道是哪一天（指上文的经期错过的第一天）
If you’re not sure when your next period isdue, you can do a pregnancy test 21 days (three weeks) after you last hadunprotected sex.
如果你不太确定下一次月经什么时候来，你可以在上一次没有采取避孕措施的房事后21天（3周）进行早孕测试。
Some very sensitive tests can be used evenbefore you miss a period. Check the packaging of your test to find out when itcan be used.
有些非常敏感的试纸可以在你月经推迟之前使用。检查一下你的测孕试纸说明，看看它什么时候使用。
What’s being tested?
（早孕测试）检测什么?
Pregnancy tests check for the presence ofthe pregnancy hormone, human chorionic gonadotrophin (HCG) in your urine.
早孕测试检测你的尿液中当前的孕激素、人绒毛膜促性腺激素。
After you conceive (when the spermfertilises the egg), your body begins to produce HCG. Around two weeks afteryou conceive, there’s enough HCG for most pregnancy tests to detect it.
当你怀孕后（精子使卵子受精）身体开始产生HCG。在你怀孕后两周左右就会有足够的HCG，大部分的早孕试纸可以检测到。
When did I conceive?
我是什么时候怀孕的？
To conceive, an egg needs to be releasedfrom your ovaries (ovulation). Ovulation usually happens about 14 days afterthe first day of your last period.
为了能够怀孕，卵子需要从卵巢排出（排卵）。排卵通常大约发生在上次月经第一天开始计算的14天。
An egg lives for about 12-24 hours afterit’s released. For you to get pregnant, a sperm must fertilise the egg withinthis time.
卵子排出后存活大约12-14小时。精子必须在这期间内使卵子受精才能使你怀孕。
Sperm can live for up to seven days insideyour body. This means, if you have sex up to seven days before you ovulate, orwithin a day or so of ovulating, you could conceive.
精子可以最多在你体内存活7天。这表示，如果你在排卵前7天同房，或在7天之内或排卵时，你可以受孕。
If you are trying to get pregnant, guidancefrom NICE advises that, for the best chance of success, you should have sexevery two to three days throughout the month. You don’t need to time it tocoincide with the days when you ovulate.
如果你准备怀孕，来自NICE的建议是：为了得到最大的成功几率，你应该在全月每2-3天同房一次。（这样）你不需要根据排卵的时间去计算什么时候同房。
Around seven days after you conceive, HCGmight be noticeable in your urine in very low levels, though this varies fromwoman to woman. Most tests need a higher level of HCG to give a positiveresult.
在你受孕后7天，尿液里可能会有很低的HCG水平，但每人和每人的情况不同。大部分阳性的测试结果需要更高的HCG水平（才能测试出来）。
Results of the test
测试结果
A positive test result is almost certainlycorrect. If you do a pregnancy test on the first day of your missed period, andit’s positive, it’s probably about two weeks since you conceived.
阳性的测试结果大部分肯定是正确的。如果你在经期推后一天测试，且结果是阳性的，那么你大约是在两周前就已经受孕。
A negative result is less reliable. If youstill think you’re pregnant after a negative result, wait a week and try againor see your GP.
阴性的测试结果可信度要低一些。如果测试为阴性但你仍然觉得自己怀孕了，等一星期以后再测，或者去看医生。
Testing after a miscarriage, abortion orectopic pregnancy
自然流产、人工流产、子宫外孕后的测试
After you’ve had a miscarriage, abortion oran ectopic pregnancy, it’s possible that a pregnancy test may still testpositive for a few weeks, even though you’re no longer pregnant. This isbecause HCG may still be present in your body.
在发生自然流产、人工流产、子宫外孕几周后，早孕测试可能还是阳性的，即使你已经不再是怀孕的状况了。这是因为也许你的体内仍然还存在HCG。