Early pregnancy tests are pregnancy tests that can detect the pregnancy hormone within the first few weeks of being pregnant. They are much like other pregnancy tests, but simply are more sensitive and thus can detect hormonal changes earlier on. To understand how an early pregnancy test works, you need to first understand how pregnancy tests in general work.

How do pregnancy tests work?

Pregnancy tests, early or otherwise, look for a special hormone in the urine or blood that is only there when a woman is pregnant. The presence of this hormone indicates pregnancy, and thus is often called the pregnancy hormone, but is actually called human chorionic gonadotropin (hCG).

When a fertilized egg implants in the uterus, the pregnancy hormone, hCG, is made. Your body automatically makes it at implantation, which usually occurs about 6 days after conception. The amount of hCG in your body increases quite a bit each day you are pregnant, so most pregnancy tests simply test for it, and the further pregnant you are, the better chance they have of recognizing the hormone, in early pregnancy tests, the test is far more sensitive, and can detect hCG even if you are not very far along. For some early pregnancy tests do not work because embryo does not implant as early as it does in other women. So, they could be pregnant, but not producing the pregnancy hormone yet because the embryo has not implanted yet.

While early pregnancy tests claim to be able to tell you if you are pregnant as early as the day you missed your period, most research shows that if you want accurate results it is best to wait about a week after missing a period, as this will ensure more accurate results and will work whether you implant 6 days after conception, or later.

With pregnancy tests, early or otherwise, there are basically two options for testing for pregnancy: a blood test and a urine test. Home pregnancy tests are urine tests, and while your doctor can perform a urine test, they generally will do a blood test. So, the question becomes which is better, and is one more accurate than another? Or, can one show if you are pregnant earlier than another?

It is important to understand that they are both testing for the same thing. They both test to see if you have the hormone hCG, one just tests the blood for this hormone, while the other tests your urine for it.

Because of advancements in science and technology, the fact is that most women, at least those that have not had trouble with conception will use a home pregnancy test first to see if they are pregnant. It is cheaper and easier than going to a doctor and waiting for results. In addition to that, they are also far more private then a blood test.

For the most accurate results, at home pregnancy tests, or urine tests, are best to tell if you are pregnant if you are about 2 weeks past ovulation. Early pregnancy tests that are HPT's (home pregnancy tests) claim to be able to detect the pregnancy hormone far earlier, although, again this is going to depend on your body more than it is going to depend on the test.

Generally if you take a home pregnancy tests and find out you are pregnant that way, you will want to call your doctor. If there is any question about whether or not you are indeed pregnant the doctor will perform a more sensitive test, a blood test, and will likely also do a pelvic exam to ensure you are pregnant, and that all signs point to a healthy pregnancy.

So, the fact is, blood tests are far more sensitive than urine tests, however, most people do not want to go to their doctor every time they think they are pregnant, and so urine tests are the norm.

There are two types of blood tests that doctors use to check for pregnancy: qualitative and quantitative. Both blood tests pick up hCG earlier in a pregnancy than urine tests can, in fact, research has shown that blood tests can tell if you are pregnant about 6 to 8 days after you ovulate (or release an egg from an ovary). So what is the difference between the two types of blood tests?

Quantitative: A quantitative blood test, called a beta hCG test, measures the exact amount of hCG in your blood. This is the most accurate blood test as it can find even tiny amounts of hCG, and is a good indicator of how far along you are, generally in the sense of how many days pregnant you are, not weeks.

Qualitative: A qualitative hCG blood test is really similar to taking a urine test as it just checks to see if the pregnancy hormone is present or not. It gives a basic yes or no answer, and if it is too early on in the pregnancy it may miss it, thus making it almost equivalent to the urine test as far as accuracy goes.

Because home pregnancy tests are by far the most commonly used method of finding out whether or not you are pregnant, let's take a look at how they work, and how you use them.

First, you get a home pregnancy test for the store, not from your doctor. You can ask your doctor for one, but they will likely suggest that you visit your local drug store and pick one up there. You do not need a prescription for one, you simply buy it over the counter. Generally you will pay around $8-$20 for the test. You may pay more for higher end brands, like E.P.T. or you may pay more because multiple tests come in the package. It is possible to purchase pregnancy tests for less, some dollar stores even sell them, but you do get what you pay for, so you may not want to trust their accuracy.

While every brand is going to be somewhat different, all home pregnancy tests work the same basic way: You have a stick (the test) and you collect urine in which you dip it in. It tests the urine for the pregnancy hormone, and has some sort of indicator to tell you whether or not you are pregnant.

Okay, so that is the jist of it, but generally the way it works is you hold the stick in your urine stream for 3-5 seconds. You then lay the pregnancy test on the counter for 2-3 minutes, at which time it will display the results. Some pregnancy tests have you collect urine in a cup, and then dip the stick in, etc. but all test urine.

It is said that for the most accurate results you will want to test the urine first thing in the morning.

The majority of pregnancy tests conducted at home will have a results window of some kind, some are digital, some say "yes" or "no" some have a line, two lines, plus sign, minus sign, etc. really, it depends on the test. However, generally the "line" contains a chemical that reacts with the hormone hCG, so if you see the line, no matter how faint, it usually means you are pregnant.

In addition to the results window, most tests have an additional window (which is often why tests are fairly confusing). The second window is called a "control indicator". This is a line or symbol that appears if the test is working properly. So, in other words, if the control indicator does not show up, the test did not work, and you will want to take a different home pregnancy test. It used to be said that one line means not pregnant, two lines mean pregnant. This is because the first line is the control indicator that says whether or not the test works, and the second is the line that shows up if you are indeed pregnant.

Pretty much whatever brand of pregnancy test you buy will have some sort of indicator on the instructions that should you want to ensure the results, take another test in a week, or visit your health care professional. This is said because in some cases you take the test too soon after a missed period and so your first test will be negative and you can take another one a week later and get positive results.

Most people question the accuracy of home pregnancy tests, but it is important to note that home pregnancy tests are actually very accurate if used correctly. Accuracy depends on the following things:

How you use them - Pregnancy tests come with directions, and expiration dates, so use them on time and the right way.
 
When you use them - Besides using them before their expiration, you want to make sure you do not take them too early. As stated previously, the amount of hCG or pregnancy hormone in your urine increases with time, so the longer you wait after missing a period, the more accurate they will be.

Who uses them - Because the amount of hCG in the urine is different for every pregnant woman, some women can take a regular pregnancy test the day after a missed period and get accurate results, and other women can take an early pregnancy test that is supposed to be more accurate, and still get inaccurate results. Some women just have to wait longer because their body does not produce as much hCG as another woman's.

The brand of test - Some home pregnancy tests are more sensitive than others. So, some tests are better than others at spotting hCG early on, if you want to find results early, then take tests designed for early testing.