Many women are anxious to find out how it will take for them to confirm whether or not they are pregnant. A pregnancy test commonly involves testing for the presence of hCG or human chorionic gonadotrophin hormone in the blood or urine. This is also called the hormone of pregnancy, because it is only detected when you become pregnant. But how long should you wait before taking a pregnancy test after you experience your implantation bleeding?
An early pregnancy test may become positive only when a fertilized egg is implanted into the wall of the uterus and a placenta starts to develop. This produces the hCG hormone which can now be detected in the blood and later in the urine.
Implantation takes place when a fertilized egg is embedded into the inner wall of the uterus. This occurs about one week after your ovulation, although this may range from 6 to 12 days. It will take another 3 to 4 days (approximately 9 to 16 days post-ovulation) for your blood test to become positive. After 2 to 3 days an early urine test for pregnancy or a Home Pregnancy Test (HPT) may turn positive. In many women this test will be positive after they miss a period, which is approximately one week after the implantation of the fertilized egg.
Although some manufacturers of home pregnancy tests say that the test gives positive results before you miss a period, only about a quarter of expectant women test positive two days before they miss a period, and less than half on the day before expected period.
How early your pregnancy can be detected and when urine pregnancy tests become positive vary according to some variables such as the time of implantation, your blood hCG levels, your urine hCG levels and the sensitivity of the test.
Time of Implantation
A blood or urine test for pregnancy is meant to detect if hCG, the pregnancy hormone, is present in either blood or urine. After you ovulate, your egg is fertilized by a sperm after unprotected sex and it then travels through your fallopian tube to the uterus. This takes about a week.
Your fertilized egg is then implanted in the lining of your uterus, which occurs about one week more after fertilization, although this may range from six to twelve days. At this time the placenta develops and starts producing the hormone hCG. This enters the blood stream, and how early this may be detected will depend on the amount of hCG in the blood 3-4 days after the implantation. hCG in your urine comes from the blood after it has filtered through your kidney. This may be detected 2-3 days after hCG in the blood is first seen. Therefore, detection of pregnancy will depend on time of implantation, when hCG becomes present in the blood 9-16 days after ovulation.
Level of hCG in the Blood
The amount of hCG in the blood may vary widely among different women, so how early a woman can test positive for pregnancy may be different for every expectant mother. If you have low levels of hCG in the blood it may take several days before it shows up in a blood pregnancy test.
Level of hCG in the Urine
The amount of hCG that shows up in the urine may also vary and it may be influenced by the amount of water you drink before taking the test. Therefore the results of your urine test may depend on how early in the pregnancy you take the test, and how concentrated or dilute your urine is, which affects the amount of hormone that is present.
Sensitivity of HPT
Different home pregnancy tests may vary in their sensitivities and this may influence how early you can detect pregnancy. Some tests can detect hCG levels as low as 20 mIU/mL which is half the level it takes to become positive when compared to that which has sensitivity for 40 mIU/mL hCG level. Tests that are sensitive to low levels of hCG may turn positive days earlier than those tests with a high sensitivity. Read the information in the package of the home pregnancy test to verify the sensitivity of your pregnancy test.