Modern Technology Revealed: How Pregnancy Tests Really Work

Today’s technology is frankly amazing. We can communicate instantly with people thousands of miles away, save money by finding cheap technology or affordable clothing online, view images and videos of everything from Aryn K dresses to wild tigers in high definition, work medical marvels and even fly into space.

It’s funny, though, how little many of us know about how those little pieces of technology in our lives work. One piece of innovation that has made a real difference to many people’s lives is the humble pregnancy test – have you ever wondered how they work?

Hormonal Changes


Between six and twelve days after a woman’s egg has been fertilized by a sperm, it will implant in the lining of the uterus. Some elements of the fertilized egg will begin to form the placenta and secrete a hormone known as Human Chroionic Gonadotrophin or hCG.

This hormone is very important in the maintenance of the pregnancy, helping to stimulate the uterus to develop and nurture the growing embryo as well as performing other functions.

Detection of Pregnancy


Since the 1970s home pregnancy tests have been available that use hCG to see if a woman was pregnant, although they have become much more sensitive and accurate with the passing of time. If your body is producing hCG it will be present in your urine.

Several different methods exist for detecting the presence of hCG in your urine. In general, for the first 20 weeks, the further developed your pregnancy the more hCG your body will produce, and the more hCG is present, the easier it is to detect.

Errors in Results


The most common form of error with a pregnancy test is a false negative – that is the pregnancy test says that you are not pregnant when the reality is that you are. This is often due to your hCG levels being too low for the test to detect.

This may be because the test was taken before the fertilized egg had implanted in the uterus or too soon after implantation for hCG levels to reach a detectable level. Some pregnancy tests can detect hCG at lower levels than others, making them more suitable for the detection of an early pregnancy.

False positives, where the pregnancy test says that you are pregnant when you are not can also occur. This may be because the test is out of date, because you waited too long to look at the results or because you have hCG in your system for reasons other than pregnancy – you may be using hCG as part of treatment for infertility, or your body may be producing hCG due to a medical condition, such as some cancers.

Post by guest blogger Carl, a writer who enjoys blogging about everything from finding affordable clothing online at affordable online boutiques to everyday technology.

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