Home pregnancy tests are quite possibly one of the best convenience inventions of all time.
100 years ago, women had to pretty much guess whether or not they were pregnant. The first obvious sign was a missed period, but as we know now, that can be due to a number of issues.
In the middle of the 20th century, doctors could test for pregnancy with more accurate results. But it involved injecting urine into a live animal and it took a long time to get the results.
Today, you can buy a pregnancy test from almost any store that carries pharmaceuticals, and you can have your answer in 2-5 minutes!
All sexually active women, unless they have been surgically sterilized, may have to take a home pregnancy test sometime in their lifetime. Even women who use birth control.
1. How Pregnancy Tests Work
All home pregnancy tests work by measuring a hormone known as human chorionic gonadotropin (hCG).
This hormone is released by the developing placenta, and traces can be found in the urine after the embryo implants in the uterus.
Pregnancy tests contain a fiber strip coated in certain antibodies that react with the hCG and a pigment indicator to produce those positive or negative lines displayed in the test window.
2. There Are Two Types of Tests
There are two basic types of home pregnancy tests. A standard test or a digital test. Both use a urine sample, but a standard test is the kind that with the color changing strip.
A digital test may give a readout saying “pregnant” or “not pregnant”, or use a symbol. (refer to the kit’s instructions to find out which type of readout your digital test will display.)
Digital tests are more expensive, but may be more sensitive. The main appeal of digital tests is that the person testing does not have to worry about reading the results of colored lines incorrectly.
3. Time To Test
The accuracy of your test results depends on when you use your home pregnancy test.
Some tests claim to give accurate dates a few days before a missed period, but most will work better one to two weeks after a missed period.
Many women get confused about how and when to use a pregnancy test.
Fertilization of the egg does not always happen immediately after intercourse.
First, a woman has to be ovulating for pregnancy to occur.
Women who are actively charting their cycles in hopes of getting pregnant will usually have an idea of whether or not they are fertile at the time of intercourse.
Most women don’t chart their cycles quite so rigorously.
On average, it is accepted that a woman ovulates (releases an egg) two weeks after her last period.
For a 28 cycle, she would ovulate sometime around day 14.
However, not all women have an exact cycle. They may have longer or shorter cycles, they may ovulate at anytime during that cycle, and they may not ovulate every month.
Since sperm can survive for several days in the woman’s body, it is possible for a woman to get pregnant several days after having intercourse, if she releases a viable egg while there are still healthy sperm alive to fertilize it.
This can throw off the results of a pregnancy test, since it takes a few more days for the egg to implant in the uterus and begin secreting hCG.
For this reason, a test taken too soon may give a negative result, even if pregnancy is already in the works.
4. Timing Of Day
If hCG is present in the urine, then typically, a test can be taken at any time of the day.
Some women have better results though it they test first thing in the morning.
This is because urine is more concentrated and the hormone levels will be stronger.
5. How To Use A Home Pregnancy Test
If you’ve never taken a home pregnancy test, don’t worry. Its easy, its non-invasive, and it doesn’t hurt.
The most important part of testing is reading the directions that are included. This is because all tests use a different method.
Some home pregnancy tests are used by holding the stick under a stream of urine.
Others require you to urinate in a cup and then dip the stick into the cup.
Another type of test has you urinate in a cup and then use a dropper to apply a few drops of urine to the test window.
Tests that require you to dip or use a dropper are a lot less messy (and you don’t have to worry about ruining the test), but they are more convenient to use in the privacy of your own home.
So if you are really impatient, and NEED to know your results as soon as you buy your test, then the sticks that you pee on are the way to go.
No matter which test you choose, you will probably have to wait a few minutes for results.
But NOT ALWAYS! If you are already several weeks pregnant, or if you have a lot of hCG present in your urine, then you may get an instant result.
6. Depends On The Woman/Pregnancy
It is very difficult to test the sensitivity and accuracy of home pregnancy tests, because how well they work depends on many factors.
Not all women will have equal results using the same test, and this could be due to testing too early, or simply not having strong enough traces of hCG in the urine.
Also, since women ovulate at different times during their cycles, it can simply be a matter of missing their period, but not being “pregnant enough” for the test to work.
However, waiting a few extra days and re-testing will usually provide an accurate result.
7. A Faint Line Does Not Mean There Is Something Wrong
When reading a test that uses two lines to reveal a positive pregnancy, one line may be very faint.
Some women feel that this means they are not pregnant, or that there is something wrong because the line doesn’t show up as dark as the control line. Not true!
If that faint line appears, then its is highly likely that you are pregnant.
The darkness of the line is not an indicator of how far along the pregnancy is, or if everything is okay. It just lets you know that you have pregnancy hormone in your urine, and you should make an appointment soon for prenatal care!
The faintness or darkness of a line can depend on the brand too, and how sensitive the test strips are.
8. Cheap Tests Are Okay
Although some pricy brands claim to be accurate as early as a few days after implantation of the embryo, (a week or two after a missed period), for the average woman, any home pregnancy test will work just fine. This includes cheap dollar store versions as well.
What matters more is whether or not a test is faulty, damaged, expired, or used incorrectly.
These issues can occur with any brand or style.
When buying a test, check the expiration date on the package.
When using a home pregnancy test, read the instructions thoroughly.
Each test will have a “control window” that lets you know if the test is working correctly.
9. But Not All Tests Are Accurate
Home pregnancy tests are considered to be 97% accurate under ideal circumstance.
Sometimes though, a test may give either a false positive, or a false negative result.
False positives are rare, but can happen. Some of the common causes of a false positive result include an early pregnancy loss (there are still traces of hCG in the urine, but no viable embryo), an ectopic pregnancy, or a molar pregnancy.
False negatives are more common. Causes may include testing too early, reading the test results too soon or too late, or testing incorrectly.
You may also get mixed results. One test may be positive, and another negative. Or a pregnancy test may show negative, but you miss your period and have pregnancy symptoms.
In either case, it is important to make an appointment with an OBGYN.
10. Other Substances Can Affect Results
Women who take fertility drugs containing hCG may not get accurate results with a home pregnancy test.
However, normal prescription and over-the-counter drugs, birth control and alcohol will not cause a false negative or positive with a home pregnancy test.
If you are on fertility treatments, or planning to use them, your doctor will probably discuss pregnancy testing with you.