Pregnancy tests work by detecting levels of the hCG hormone in your urine. Your body makes this hormone after a fertilized egg attaches to the wall of your uterus, which usually happens about 6 to 12 days after fertilization. The levels of hCG rise quickly, doubling every 2 to 3 days. At Options Medical Clinic, we use only the highest lab-quality pregnancy tests. Our tests are 99% accurate, so you can be sure of the results. Plus, one of our medical professionals can discuss your other symptoms as well.