Implantation is a process in which the ovum invades the endometrial lining. As a result, the affection of several vessels lead to implantation bleeding.

To confirm the pregnancy, a woman might take a blood test at home or in a clinic, based on the observation of HCG (human chorionic gonadotropin), a hormone in pregnancy, in her urine. The reliability of these tests according to the level of the HCG at a particular stage.


Many people wonder “How long after implantation bleeding can I test?” In general, a pregnancy test would be most precise from 6 to 8 days after the implantation bleeding. However, the last statement of pregnancy is just up to your doctor, who would need to carry out an ultrasound test.

Implantation is probably one of the initial important stages in the development of a fetus, which consists of 3 different stages:

  • The attachment of the ovum
  • The implantation at the endometrium, occasionally followed by implantation bleeding
  • Last fetal fixation and the healing of mucous lining

In general, this process begins after 6 days of fertilization and is totally complete after 12 days. In addition, it is followed by the secretion of various bioactive substances and hormones by several structures of the mom’s organism and the fetus.

As the follicle is emptied right after the ovulation, its impact on the earliest phases of pregnancy would be about the yellow body maintenance. Before the forming of placenta, progesterone is produced mainly by the yellow body, while HCG is generated by a special component of the ovum. Therefore, detecting and measuring the level of HCG in the urine and the blood of a mother is what a pregnancy test is based on.

When is appropriate to test after implantation bleeding?

A lot of pregnancy test at home claim to have the ability to “find out the answer after the very early time of the delay”. But is that actually correct? The true is that this type of test could offer an exact result just if the following 2 elements are taken into consideration:

1. Sensitivity of this particular test

2. The level of HCG in the tested substance

This hormone level in urine or blood depends on the particular time after fertilization. In the normal case, this number often increases twice for each 48 to 60 hours throughout the first 8 weeks.

Therefore, about 4 to 5 days after the implantation, the amount of HCG in a sample of blood is approximately 25 mIU/ml. In general, it could be found by analyzing a serum of blood, which is taken from the vein in a special laboratory. In another 1 or 2 days, the level of HCG reaches the similar number in urine (25 mIU/ml), but it is better to take a home pregnancy test in the morning.

Is it reliable to take a pregnancy test after implantation bleeding?

Even having measured the accurate days that you need to wait for an exact test result, you also have to bear in your mind that the level of HCG would increase less intensively or even slower in the situation of ectopic pregnancy. In addition, the risks of miscarriage also result in the decrease of the HCG amount.

Those objective standards are not free of exception (from 15 to 17 per cent). Nevertheless, the difference of false negative test would be possible. In the same way, false result of a negative pregnancy test could be because of too early examining when the level of HCG has yet to reach the minimal number, depending on detection.

Reasons for a false positive result in pregnancy test:

  • Error in laboratory
  • High level of lipids in the blood
  • The destruction of blood cells
  • A tumor which generates chorionic gonadotropin

How to confirm a positive pregnancy test after implantation bleeding

From 6 to 8 days after implantation, it is highly suggested to confirm the result if you take a positive pregnancy test. In general, it could be achieved with the support of careful attention to some common pregnancy signs, including:

  • Vomiting and nausea
  • Increased fatigability
  • Regular urination
  • Period delay
  • Sore and swollen breasts

Nevertheless, it is the gynecologist who would cast back or confirm the fact of pregnancy by making an ultrasound test.


To sum up, pregnancy test at home plays an essential role in the screening of early pregnancy, but it is not suggested to have complete credit in the result. In fact, you could not get a 100 per cent guarantee for the precision even when you take this test later than one week after the implantation bleeding. Therefore, you should have the result checked again by a professional specialist.

Nancy D. Richardson

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