Some girls test positive with early pregnancy test strip after having sex. But such excitement disappears when HCG blood test shows negative.
 
To know why such phenomenon occurs, we should start from the methodology of early pregnancy test strip. Early pregnancy test strip detects human chorionic gonadotrophin (HCG) in urine. When HCG continues to rise and go beyond normal level, dark lines will show on test strip and become darker and darker, from pink, red, to crimson.

Normally, when a fertilized egg cell adheres to the wall of uterus, HCG will be released and then urine HCG level will rise.
 
Why is home test positive when I am not pregnant?
 
Mostly caused by false operation. For example, test strip should be interpreted within certain time (usually 5 to 10 minutes), or it would be oxidized over that time and show a false positive result.
 
False positive result may also be caused by abnormal pregnancy, such as biochemical pregnancy. Home pregnancy test cannot confirm normal pregnancy or not.
What is biochemical pregnancy?
 
It refers to the pregnancy that stops growing and resolves after implantation and HCG secretion into mother’s blood and urine to a detectable level. HCG in blood and urine rises once but not continuously. Ultrasound cannot detect gestational sac, and the dark lines on positive test strip may turn light or even colorless.
 
In fact, biochemical pregnancy is not rare. But most biochemical pregnancy occurs quietly and cannot be noticed without medical check. With the wide application of assisted reproductive technology, biochemical pregnancy is gaining increasing attention for its 50-60% incidence.
 
Therefore, if the two dark lines gradually turn light or your blood test shows decreasing HCG level or no gestational sac can be scanned under ultrasound, it may be biochemical pregnancy.
 
Why does biochemical pregnancy occur?

1. Low quality of egg cell
 
Low quality of egg cell determines the quality of embryo, and thus trigger biochemical pregnancy.

2. Low quality of embryo
 
Biochemical pregnancy is a kind of natural selection. Low quality of fertilized egg cell—such as chromosome abnormality—will hinder implantation and cause biochemical pregnancy.

3. Problems with endometrium
 
Endometrium is the soil for implantation. Its thickness, shape and receptivity will influence the pregnancy. Maldevelopment, Asherman’s syndrome, submucosal myoma of uterus, endometrial polyps may also result in biochemical pregnancy.
 
Besides, biochemical pregnancy is also related with function of ovary and corpus luteum, immune factors, semen quality, etc.
 
Why should I use high-sensitivity early pregnancy test strip?
 
High-sensitivity test strip can detect changes of HCG concentration earlier, with no interference with result accuracy. The earlier a test strip detects HCG changes, the earlier it can alert a mother to prepare for pregnancy and to know of conditions of herself and her baby.
 
HCG in urine will rise as pregnancy progresses during early phase and will be easier for detection. Morning urine is recommended for testing, and further inspection is needed after dark lines appear on your test strip.
 
Early Pregnancy Wondfo Test Strip demonstrates you the HCG level in your urine. We help you to catch the chance of conception.