Experiencing pregnancy symptoms but negative test results may be disheartening for women trying to conceive. The tests for pregnancy involve checking your blood or urine for the human chorionic gonadotropin (hCG) hormone. Home pregnancy tests detect the presence of the hCG hormone in urine. hCG is produced in the body after the implantation of a fertilized egg in the uterus, and its levels increase in blood and urine during the first trimester. However, these tests are not 100% accurate and may produce false-negative or false-positive results