Most women who suspect they're pregnant have their suspicions confirmed or dismissed by means of a urine test that measures the level of the hormone human chorionic gonadotropin (HCG), which is produced by the placenta and is present only during pregnancy. A standard urine test given by doctors and clinics is accurate for most women starting about 27 days after conception, or about 2 weeks after a missed period. A newer test, known as the urine tube test, can be accurate as early as the first day after a missed period, or 2 weeks after conception.
Home Pregnancy Test
Instead of going to a doctor or a clinic, many women prefer to use home pregnancy test kits. These over-the-counter urine test kits are basically the same as the newer tube tests given by doctors and are just as accurate when used properly. With urine test, only about 3 to 5 percent of positive results are false positives, indicating that a woman is pregnant when she is not. But about 20 percent of all negative results are false negatives, indicating that a woman is not pregnant when she is. Reasons for the false negatives include taking a test too early in the pregnancy, using a urine sample that's contaminated or that's not from the first urination of the day, when HCG is most concentrated, and having an ectopic or other abnormal pregnancy. If a test is negative and you still suspect you're pregnant, see your doctor. He or she may suggest a blood test, which is more sensitive in detecting HCG than urine tests and can establish pregnancy within 9 to 12 days of conception. Given by doctors and clinics, blood tests are more expensive than urine tests and are generally used only when there's doubt or when a very early diagnosis of pregnancy is needed.
Starting about 6 weeks after a missed period, a doctor can detect a pregnancy by performing a pelvic exam. At this stage of a pregnancy, the uterus softens and changes size and shape, and the cervix may become bluish because of increased circulation.