Pregnancy testIt isn’t rocket science, but it may as well be. Women who are anxiously awaiting the answer to the most anticipated question, “Am I pregnant or not?” have to pay attention to little details, calculate correctly, and use the proper equipment. If you’re in the middle of this exciting equation, buckle up and get ready for a short course in pregnancy test taking 101:

What Is It?

A pregnancy test does just what it says it does — it determines if you’re pregnant or not. There are two ways to test for pregnancy: a blood test and a urine test. A blood test can detect pregnancy earlier — about six to eight days after ovulation — but it takes longer to get the results and must be administered in a doctor’s office, according to WebMD. Because of that, urine pregnancy tests are used more often. You can buy a home pregnancy test without a prescription at most grocery and drugstores.

How Does It Work?

Soon after a fertilized egg attaches to the wall of a woman’s uterus, a hormone called human chorionic gonadotropin (hCG) is produced and released into the body. It usually happens (but not always) about six days after fertilization, according to WebMD. If you’re pregnant, the levels of hCG continue to grow, doubling every two to three days. A pregnancy test samples your blood or urine to see if it contains any hCG, commonly known as the pregnancy hormone.

When Can I Take One?

Many women wait about a week after their missed period to take a pregnancy test, but some tests can be taken earlier than that. Check the brand’s label, and when in doubt, take one test before your missed period and one after. WebMD suggests taking the test first thing in the morning when your urine is more concentrated. If you consume large amounts of fluid right before taking a test, your urine may be too diluted to detect faint traces of hCG, especially if you’ve just conceived.

Is It Accurate?

The accuracy of your pregnancy test depends on several factors, including how closely you follow the instructions, the sensitivity of the test, and when you take it. Usually, if you get a positive result, you’re pregnant — no matter how faint the line, color, or sign. But in some rare cases, it’s possible to get a false-positive, according to the Mayo Clinic. This could happen if you’re on certain drugs, including tranquilizers or hypnotics, or if there’s blood or protein in your urine. It’s also possible to get a false negative. This could happen if the test is taken the wrong way, too soon, or past its expiration date. Usually, though, most tests are accurate. Some brands even claim to be 99 percent accurate, while most are about 97 percent accurate, according to WebMD.

Other Early-Pregnancy Signs

On their own, these symptoms may mimic those of menstruation; when combined, they can be early signs of pregnancy:

  • You’re moody
  • You feel sick
  • You’re exhausted
  • You’re constipated
  • Your breasts are sensitive or swollen
  • You’re spotting