Pregnant but negative test may be caused by expired pregnancy test, contaminated pregnancy test, or not using the test properly as required. 1. Expired pregnancy test: If the pregnancy test is not within the shelf life, it will affect the test result, thus the situation of pregnant but the test is negative. 2. Contamination of the pregnancy test: If the pregnancy test is damp, it will lose its effectiveness. In addition, if the pregnancy test is contaminated by certain drugs, it will also appear pregnant but the test is negative. 3. Failure to use the pregnancy test as required: If the morning urine is not used for testing, the test may also be negative. If a woman is diagnosed as pregnant but the test is negative, it is recommended that she consult a doctor in a timely manner, complete the relevant examinations under the guidance of the doctor, and go to the maternity clinic on time.