It is important to understand how pregnancy tests work when you are thinking of using them. When a woman is pregnant she makes a hormone called hCG. The placenta starts making it as soon as the fertilized egg reaches the uterus and implants into the wall. HCG is detectable in your urine and is responsible for physical changes when pregnant such as tiredness, sickness, cravings and nausea.
The best time for a pregnancy test is after a missed period as the levels of hCG are high then and easily detectable. On the market are sensitive tests such as Early Response and Clearblue Easy. These can detect lower levels of hCG so can be used earlier, even before a missed period. They can detect levels 20mIU up, so timing is important here. 3 weeks after conception hCG levels could be anywhere between 5 to 50mIU, it varies between women. If your levels are low, the test will give a negative result despite you being pregnant.
The embryo needs anywhere between 6 to 12 days to make that journey to the uterus. During that time there is no hCG and so a negative result would show. A woman should wait at the very least 12 days after conception before testing – and even then it may be too early even for a sensitive test. Note also that if you have taken fertility drugs to conceive a home pregnancy test can give you a false positive result.
Home Pregnancy tests vary in how results are displayed but all test the same thing. If you are worried about getting confused over lines, the digital ones may be for you. They start at around $8 going up to $20. Unless using a sensitive test, try to wait till after your missed period. Some other pointers are:
Use your first urine of the day as the hCG is easier to detect in this more concentrated urine. At least 4 hour urine is best. The leaflet needs to be read carefully and followed exactly for the best accuracy. You should only read the test at the time the instructions say, usually 1 to 3 minutes after peeing on the stick. After that the test is no good. A doctor can do a blood test if you are having problems.
All there is to know about early pregnancy tests and pregnancy testing in general. Today’s special: how to fake a pregnancy test