Interpreting Pregnancy Tests

Written by Jill // March 17, 2010 // Pregnancy // No comments

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Pregnancy tests, accuracy, confusion and taking them early. AAAgh. Interpreting pregnancy tests can be confusing at best. One line? Two? Plus? Minus? I spent 15 minutes in the shower wondering how I was going to tell my husband that we had just conceived a third child accidentally. Until I realized that although there was a line on the pregnancy test, it wasn’t a plus sign and said line was going the wrong way. I had thrown away the instructions, you see, and there were no markings on the test with which to search for directions. Why aren’t these tests standardized? The new (expensive) ones say ‘not pregnant” or ‘pregnant‘. How long did it take to come up with that brilliant plan? Most have a plus sign and a control window, a single parallel line and a control window, or a parallel line and a control window (The control makes sure that your urine has been plentiful enough to reach all the way to the back.)

How Pregnancy Tests Work

Most pregnancy tests are accurate after the first day of a missed period. Many women’s cycles are not regular, and the earliest a test can be taken varies depending on the cycle as well as the timing of implantation (between 1 and 6 days after fertilization). Pregnancy tests rely on the presence of the hormone human chorionic gonadotropin (hCG), secreted by the placenta shortly after fertilization. hCG levels double about every two days in a pregnant woman, so the test is much more reliable two weeks after conception than one week later.

Basically, you can wait a while and then do a test, or drive yourself (and your bank account) crazy by trying them early and often. Just don’t throw away the instructions.

You might also want to read about early pregnancy signs and reasons for late periods.