Pregnancy Testing

Pregnancy tests measure a hormone called human chorionic gonadotropin (HCG). The placenta produces this hormone during pregnancy. The embryo begins to produce this hormone as soon as it attaches to the wall of the uterus – often as soon as eight to 10 days after conception. Although each woman is different, the HCG level usually doubles every 48 to 72 hours. How soon a pregnancy can be detected depends on:

• how much HCG is being produced
• the type of pregnancy test used (blood or urine)
• the amount of HCG the test measures

Home test kits can be used to test your urine, if you think you are pregnant.

Home Pregnancy Tests

Home pregnancy tests are used to test your urine. They generally react by changing colour if they detect HCG in your urine. The smaller the amount of HCG the test measures, the earlier it will detect your pregnancy. Generally, one of these kits can detect a pregnancy 10 days to two weeks after ovulation, around the time of your first missed period, though some of the newer tests claim they can detect pregnancy earlier than that. A positive test with a home testing kit is usually correct; however, a negative test does not necessarily prove you aren't pregnant. A repeat test a week later might be positive.

Pregnancy Testing at Your Doctor's Office

It is wise to confirm a home test result with a test at your doctor's office. This is also a good time for you and your doctor to start talking about prenatal care. The pregnancy test done in the doctor's office is typically a blood test that measures levels of HCG. These tests can tell your doctor the exact amount of pregnancy hormone in your blood. Abnormal levels of beta-HCG are an early warning sign of problems.

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