Please note: this is the level of hCG in the blood. The level of hCG in the urine lags behind these indicators by 1-3 days.
Most pregnancy tests are accurate as early as the first day of your expected (but not arrived) period. This means that 12-14 days have passed since the meeting of the egg and sperm. It is important to carry out diagnostics with strict adherence to the instructions.
The level of human chorionic gonadotropin in the blood rises during a night's sleep. A similar process occurs with urine. During a night's sleep, a woman does not go to the toilet and does not consume fluids.
This allows the kidneys to release a concentrated portion of the biomaterial into the bladder. In order for the test to show pregnancy from the first day of missed periods, it should be performed on morning urine.
On the day of the expected menstruation, if girls do testing, they usually do it in the evening. In the morning and during the day, they wait for the menstruation to begin, and if it is absent by the evening, then they perform a diagnosis.
Often the result is negative, even in the presence of pregnancy. The reason for the negative response is that the urine is not concentrated. After 2 days of the absence of the expected menstruation and later, testing can be carried out not only in the morning.
During this period, the concentration of hCG is so high that the test will not be mistaken even in the evening.
There are several reasons why the test may not show pregnancy on the first day of delay:
• late ovulation and, accordingly, implantation;
• incorrect calculation of the day of the expected menstruation;
• unstable cycle;
• a small amount of "pregnant" hormone in the urine;
• ectopic pregnancy.
In the latter case, the level of hCG is also elevated, but it does not grow as fast as with normal localization of the fetal egg, so the result may be negative or weakly positive (that is, the second strip is weak, fuzzy).
If on the 3rd day of the delay, the test shows one strip, and the instructions were strictly followed, then one can doubt that the conception took place. Perhaps there was a hormonal failure in the body or this month there was no ovulation at all. Anovulatory cycles are characterized by late periods due to low progesterone levels.
With a delay, you can take a pregnancy test at any convenient time, and usually it already shows a reliable answer. If in doubt, it is better to double-check the diagnostic results after 1-2 days.