There are several phenomena that cannot detect pregnancy

The phenomenon of undetectable pregnancy mainly includes failure of fertilized egg implantation, premature testing time, improper testing methods, abnormal hormone levels, ectopic pregnancy, etc. These situations may lead to false negative results in early pregnancy test strips or blood tests, which need to be comprehensively judged in conjunction with clinical examinations.

1. Fertilized egg not implanted

After the formation of the fertilized egg, implantation is completed within 6-12 days, during which the level of human chorionic gonadotropin in the body has not yet increased. If the hormone cannot be detected in urine or blood during pre implantation testing, false negative results may occur. Suggest retesting after a one week delay in menstruation or confirming pregnancy status through ultrasound examination.

2. Early detection time

Early pregnancy test strips need to detect hormone changes 7-14 days after the implantation of the fertilized egg. If tested immediately after intercourse during ovulation, the most sensitive test strip may also be negative. Clinical recommendations suggest starting from the first day of the last menstrual cycle and testing 35 days after cessation of menstruation, with an accuracy rate of over 95%.

3. Improper testing methods

The use of expired test strips, failure to follow instructions, and excessive urine dilution can all affect the test results. The hormone concentration in morning urine is relatively high, making it suitable as a test sample. If the initial test is negative but the menstrual cycle continues to be delayed, the test can be repeated every 48 hours, or serum β - HCG quantitative testing can be used instead.

4. Abnormal hormone levels

Endocrine disorders such as polycystic ovary syndrome and luteal insufficiency may lead to delayed HCG secretion. Some pregnant women experience slow hormone doubling and require dynamic monitoring of changes in blood HCG levels. Abnormal thyroid function or taking hormone drugs may also interfere with the accuracy of test results.

5. Ectopic pregnancy

During ectopic pregnancy, the embryo implants in non uterine areas such as the fallopian tubes, and HCG levels are often lower than in normal pregnancies and rise slowly. The patient may experience symptoms such as vaginal bleeding and severe lower abdominal pain, but the early pregnancy test strip may be weakly positive or negative. Diagnosis should be confirmed through vaginal ultrasound and blood HCG monitoring to avoid the risk of fallopian tube rupture. For women with regular menstrual cycles, if they experience early pregnancy symptoms such as amenorrhea and breast tenderness but test negative, it is recommended to record basal body temperature and observe the phenomenon of prolonged luteal phase. Avoid intense exercise and mental stress, maintain a balanced diet, and supplement with folic acid. All suspected pregnancy cases must ultimately be diagnosed through hospital blood HCG testing and ultrasound examination. Do not rely solely on self-test results to delay the diagnosis and treatment of emergencies such as ectopic pregnancy.