Pregnancy tests

All pregnancy tests work by detecting a hormone called human chorionic gonadotropin (hCG) or the pregnancy hormone in the urine or blood that is present only when a woman gets pregnant. hCG is produced when a fertilized egg implants in the uterus which typically happens about six days after the egg and sperm unite. The amount of hCG rapidly builds up in the body with each passing day that you are pregnant.

Different types of pregnancy tests

There are two types of pregnancy tests. One checks for the hormone, hCGin the blood and is usually done by the doctor, while the other checks the urine for the hCG hormone. There are two types of blood tests:

• Qualitative, which measures whether the HCG hormone is present
• Quantitative, which measures how much HCG is present

The blood test is done by drawing a single tube of blood and sending it to a laboratory. You may have to wait a few hours to get the results. The urine HCG test is normally carried out by placing a drop of urine on a prepared chemical strip. It takes 1-2 minutes for a result. The urine test can be done either at a doctor's office or at home using a home pregnancy test (HPT). Most women these days initially use an HPT to find out if they are pregnant since these kits are inexpensive, private and easy to use. They also ensure high accuracy if used correctly and at the right time.

How do you do a home pregnancy test?

There are different types of home pregnancy tests (HPTs). Many drugstores sell HPTs over the counter and they are inexpensive. But the cost varies depending on the brand and the number of tests that come in the box. Most HPTs require the user to hold a stick in the urine stream while still others involve collecting the urine sample in a cup and then dipping the stick into it. Then the woman needs to wait a few minutes following which she should inspect the result window.A line or plus symbol indicates that you are pregnant.

How accurate are home pregnancy tests?

Home pregnancy tests (HPTs) can be quite accurate but the accuracy depends on:

• How you use them: Be sure to check the expiration date and follow the instructions as given on the box.
• Who uses them:Every woman ovulates at a different time in her menstrual cycle. Moreover, the fertilized egg can implant in a woman's uterus at different times andhCG is only produced after implantation occurs. In some women, implantation does not occur until after the first day of a missed period. So, HPTs will be accurate only a day after a missed period for few women but not for others.
• When you use them: The amount of hCG or pregnancy hormone in your urine increases with time. So, the earlier you take the test after a missed period, the harder it is to spot the hormone. Moreover, testing the urine first thing in the morning can greatly increase the accuracy.