How early can I take a pregnancy test?
An early pregnancy test becomes positive only after the fertilized egg has arrived inside the uterus and implanted into the uterus and then sent enough amounts of hCG, human chorionic gonadotropin, the pregnancy hormone, into your bloodstream, and from there into the urine.
The urine pregnancy test (home pregnancy test or HPT) checks for the presence of the pregnancy hormone hCG in the urine. hCG is made by the implanting blastocyst and first appears in the maternal blood around implantation, on average 9 days (with a range of 6-12 days) after ovulation. Blood hCG levels then rise rapidly to reach a peak at 7-10 weeks, and then decline after that time.
With most current pregnancy test kits, hCG can be detected in the urine as early as 3-4 days after implantation, though it often takes longer. If you are pregnant, on the day you miss your period about 74% of HPTs will be positive. So a negative pregnancy test is normal in about 26% of all pregnancies, and you may have to retest until you know the most accurate results.
A negative HPT result 10+ days after the missed period makes a pregnancy unlikely. Positive pregnancy test results can show up any time before or after a missed period.
|Expected Menstrual Period||How often is the
pregnancy test positive?
|3 days before expected period||51% positive|
|2 days before expected period||62% positive|
|1 day before expected period||68% positive|
|Day of expected period||74% positive|
|1 day after expected period||79% positive|
|2 days after expected period||85% positive|
|3 days after expected period||90% positive|
|7+ days after expected period||96% positive|
Blood Pregnancy Test
The blood pregnancy test is usually positive within 3-4 days after implantation or about 9-10 days after fertilization and ovulation, which is roughly 5-6 days before a missed period.
What determines when a home pregnancy test becomes positive?
1. Timing Of Implantation
Detection of hCG depends on the timing of implantation, so hCG can normally be detected in the blood between nine and 16 days after ovulation. Urine hCG can be detected about two to three days after blood hCG can first be seen.
There is a wide normal variation of hCG levels, both in the blood and the urine, and this wide range changes the timing of how early can pregnancy be detected. If a woman has a normal but low blood hCG levels, then it can take several more days for it to show up on a pregnancy test.
Urine hCG levels change over the course of the day depending on how much you drink and how diluted or concentrated the urine. How early a pregnancy can be detected depends on the urine concentration and the quality of the early pregnancy test. If you drink a lot of fluid, the urine may be too diluted early on in pregnancy to achieve an hCG concentration adequate enough for a positive test.
4. Sensitivity Of The Pregnancy Test
Different pregnancy tests have different sensitivities and that has an impact on how early can pregnancy be detected. The lower the sensitivity, the earlier a pregnancy test becomes positive. Sensitivities are indicated in mIU/mL, the lowest amount of hCG in the urine that tests positive. A sensitivity of 20 mIU/mL requires one-half the hCG level to be positive when compared with a 40 mIU/mL sensitivity level, and it may become positive several days earlier than the pregnancy test with a higher sensitivity. Make sure you read the package of the pregnancy test to determine your pregnancy test's sensitivity.