Home Pregnancy Testing

If you observe any of the usual early signs of pregnancy, like morning sickness and breast tenderness, then you are likely to want to confirm whether or not you are actually pregnant. Fortunately there are a number of tests available these days which are easily purchased from supermarkets and chemists and can give you a fairly reliable indication of whether or not you are pregnant.

How do pregnancy tests work?

As your body begins a pregnancy, it undergoes a number of changes, the most significant of which are major increases in the levels of certain hormones. These hormones actually stimulate the other changes your body needs to undertake in preparation for a pregnancy. One of these hormones, called human chorionic gonadotropin (usually shortened to hCG), is only produced during pregnancy by specific cells, and can in fact be detected in urine, hence giving birth to the popular pee-stick pregnancy test.

hCG is a very reliable measure of pregnancy, and the test itself works by means of tiny molecules called antibodies which are fixed to the surface of the testing stick. These are specially designed to bind to hCG, forming the tell-tale blue line which indicates a positive result and a pregnancy.

How accurate is the pregnancy test?

The hCG test does have some limitations however. It can only indicate pregnancy after implantation, which is usually between 6 and 12 days after the release of an egg during ovulation. Implantation is the point at which a fertilised egg makes its way to the lining of the womb and essentially implants into it to begin developing. Because of this the hCG test is only really useful within a particular timeframe. If performed too early, the hCG test is much more likely to yield a false positive.

If you are receiving the hCG injections from a doctor as part of an on-going fertility treatment, then the hCG test will always give a false positive as the hormone which in other circumstances is only present during pregnancy is in fact circulating in your bloodstream. Certain illnesses can cause an increase in levels of hCG as well.

Otherwise, generally speaking home tests are reputed to have an accuracy of about 97% when used by a trained professional, which is actually reduced to 75% during home use which is attributed to incorrect administration of the test. There is some variation between different products from different manufacturers as some pregnancy tests are designed to be sensitive to lower amounts of hCG, and can hence be more accurate.

Using a pregnancy test

The correct use of a home pregnancy test is a big part of how reliable the results you get will be. These tests will come with a set of instructions on how to use them, and these will generally tell you how exactly to get a reliable result.

You will need some privacy for this test as you will need to urinate on the test stick, a few drops are usually all that it needs. The test will typically take between 2 and 5 minutes to show a result, anything outside of the window mentioned by the instructions that come with your product won’t be as reliable.

Variations on the classic home pregnancy test

More sensitive tests now commercially available can tell you how long you have been pregnant for. These base their results on the fact that the levels of hCG present in your urine increases in a stepwise manner, doubling every 2 or 3 days. Generally however, the blood hCG test your doctor can perform will be more reliable.

Confirming a home pregnancy test

There are a number of different ways of confirming and elaborating on the results of a home pregnancy test. A blood hCG test is a more accurate version of the home pregnancy test as it quantifies the exact amount of hCG circulating in your blood stream. There is a sequential increase in the levels of hCG in your system that can be used to determine how far along the pregnancy you are, and if the quantities of these hormones do not increase as they should, your doctor can determine whether or not there is something wrong with the developing pregnancy.

Obstetric ultrasonography is an ultrasound technique which can be used to confirm a pregnancy. The ultrasounds will actually be performed regularly to ensure the correct growth and development of the child.

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