According to the American Pregnancy Association, the egg implants into the uterus six to twelve days after ovulation. After implantation, the body begins to produce the pregnancy hormone, hCG (human chorionic gonadotropin), which is what pregnancy tests detect to indicate a positive result. The hormone level doubles every 48 to 72 hours throughout the first trimester.
Home Pregnancy Tests
The American Pregnancy Association states that home pregnancy test are 97% accurate when used correctly. Although many tests indicate you can test as soon as five days before your next period, the most accurate results will be obtained after you have missed your period and the earliest a test can provide an accurate reading is 14 days after conception. Tests differ in sensitivity in detecting hCG in the urine. When the egg implanted in the uterus determines how early hCG will be built up in the system enough to produce a positive result. You can test early and possibly get a positive result. However, if the result is negative, wait until you miss your period and test again as the results will be more accurate at that time.
Blood tests are performed in doctors offices and detect the level of hCG in the blood. Blood tests are generally more sensitive than urine tests and can detect a pregnancy earlier than urine tests. However, most doctors will not perform a blood test until you have missed your period to reduce the possibility of a false result.
If you are charting your cycles to predict ovulation, you may have another indicator of pregnancy. Basal body temperature has a sudden rise after ovulation and remains steady until menstruation starts when it drops back to pre-ovulation levels. Some women will experience a second spike in basal body temperature after ovulation when implantation occurs. If this second spike is maintained and you have been accurately taking and recording your temperature each morning, this may be an indication of pregnancy even before you miss your period.
Early Pregnancy Symptoms
Some women experience pregnancy symptoms before a missed period beginning as early as when implantation occurs. Early pregnancy symptoms can include morning sickness, a strong aversion to certain smells, increased breast tenderness and increased urinary frequency. Though these symptoms do not apply exclusively to pregnancy, they can be an early sign that successful conception has occurred.