The failure to detect pregnancy test paper may be caused by non-pregnancy, short duration of pregnancy, biochemical pregnancy and other reasons.
1. not pregnant: women with normal menstrual cycles, although the chances of conception will increase after intercourse during ovulation, but does not guarantee 100% pregnancy, when not pregnant, the test paper will not detect, menstruation will come on time.
2. Short pregnancy: early pregnancy can be early pregnancy test paper through the detection of HCG (human chorionic gonadotropin) in the urine to determine whether the pregnancy, regular menstrual cycle of women can be in the menstrual cycle overdue about 1 week when the test, but when the test in advance due to the short period of time of the pregnancy may not be detected, you can be in the guidance of the doctor for retesting.
3. Biochemical pregnancy: due to the failure of fertilized egg implantation leads to a transient elevation of blood HCG, and early pregnancy test can not be detected, manifested in the vaginal bleeding before the menstrual period, similar to the amount of menstruation, can be combined with the clinical manifestations and blood HCG can assist in the diagnosis.
When the pregnancy test paper can not be detected, the doctor needs to combine with the medical history to assess, if necessary, perfect blood HCG to further clarify.