Pregnancy Test at Implantation

Women who are actively charting their fertility signs or are otherwise very excited and hopeful about becoming pregnant might want to take a pregnancy test as early as implantation. The at-home tests of your urine cannot detect the HCG that occurs immediately following implantation because it first enters your blood stream and then is filtered into your urine. Therefore, a pregnancy test at implantation would render a negative result, even if you are carrying a fertilized egg. Within about 3 – 4 days after implantation, you will most likely be able to obtain a positive pregnancy test from your first morning urine, assuming you are using a sufficiently sensitive test.

How Can I Tell If Implantation has Occurred?

The signs of implantation can be difficult to identify even if you are charting because they may occur in pregnant and non-pregnant charts and can only be considered retrospectively. In a minority of women, some amount of implantation spotting may occur, although if you are not charting, it is possible to mistake this for mid-cycle, ovulatory spotting. Other signs of implantation include a dip in the generally higher, post-ovulatory basal body temperatures between 6 and 8 days post-ovulation, although this “implantation dip” may also occur in non-pregnant charts as a result of normal daily temperature fluctuations. Implantation cramping has also been reported, although again, this may be mistaken as ovulatory cramping if you are unsure where you are in your menstrual cycle.

How Soon After Implantation Can I Accurately Take a Pregnancy Test?

Only a blood pregnancy test can detect HCG immediately after implantation, and many blood tests used in clinician’s offices are not designed for such early detection of HCG and may give a false-negative result. If you have been working with a reproductive physician and undergoing in vitro fertilization or intrauterine insemination, it is possible that you will go in for repeated blood tests to not only detect HCG but also to quantify the HCG level to ensure that your circulating HCG levels are doubling every 36 hours of so, which is indicative of a healthy singleton pregnancy. If your HCG levels double more quickly, it is possible that you are carrying more than one fetus. On the other hand, HCG levels that plateau or decrease over time are considered non-reassuring and indicative of a potential miscarriage.

In summary, a home pregnancy test cannot be accurately taken at implantation, although a few days after implantation maybe enough time to yield a positive pregnancy test. For those women who desperately want to know their pregnancy status, taking a blood test near implantation may be a viable option.

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