The Science Behind Taking A Home Pregnancy Test

Taking a home pregnancy test can be nerve wracking, especially when you have a sense of uncertainty long after the result. A home pregnancy test is designed around a very crucial pregnancy hormone called the human chorionic gonadotropin (hCG); it’s the detection of this hormone that gives you a positive or negative result. Here are a few facts about home pregnancy tests that can help make this entire process a little easier.Everything You Ever Needed To Know About Ovulation

How do home pregnancy tests work?
Pregnancy tests are designed to tell you if your urine contains human chorionic gonadotropin (hCG). This hormone is produced right after a fertilized egg attaches to the wall of a woman’s uterus (implantation).This usually happens – but not always – about six days after fertilization.
A home pregnancy test contains a special reagent dye that binds to hCG if present in the urine and appears as a visible test line in a specific colour (depending on your pregnancy kit).

How do you use a home pregnancy test?
For best results try testing first thing in the morning, when your urine is most concentrated and will contain a good concentration of hCG. Read the directions carefully because they vary with different brands. Some require you to urinate in a cup and then use the dropper provided to place a small sample in the testing well. With others, you can urinate directly onto the testing device. And some will let you do either. It may take up to ten minutes to show your result.

When is the best time to take the test?
hCG becomes detectable in the urine ideally six to ten days after ovulation, if fertilization has occurred. This may not be the case each time and it is possible for the accuracy to vary depending on the pregnancy test that you are taking. Some tests claim to be able to give a 97% accurate result even if you take the test on the day that you miss your period, but the most reliable time would be to wait a week after you missed your period to be absolutely certain.

How sensitive are these home pregnancy tests?
New products come out frequently, and manufacturers keep making improvements. To get the most sensitive pregnancy test observe the information given on the packages. Most of these tests provide information on what concentration of hCG is detectable by them. They report the lowest concentration of hCG in milli-International Units per milliliter (mIU/ml) of urine. For example, a pregnancy test that claims to be able to detect hCG at 20 mIU/ml theoretically should be more sensitive than one that claims to detect it at 50 mIU/ml. The lower the concentration reported, the more sensitive the test.

Is it possible to get a false-positive or a false-negative result?

A false-positive result means the test shows a positive result but you actually are not pregnant. A false-negative result means the test shows a negative result but you actually are pregnant.

False-negatives are far more common then false-positives. You can get such a result if

  1. The test is past its expiration date.
  2. You took the test the wrong way.
  3. You tested too soon.
  4. Your urine is too diluted because you consumed large amounts of fluid right before the test.

If you get a negative pregnancy test result, try retesting within about a week to double-check.
A false positive is a rather rare occurrence, but it is possible if you are using hCG-containing fertility drugs.

If you are still doubtful about your results the best way to confirm is to contact your doctor and get a blood hCG test which is the most accurate method of detection.

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