Pregnancy can be detected eight days after intercourse. Because sperm can survive in a woman’s body for 72 hours, it is possible for a patient to conceive on the day of intercourse and within three days after intercourse as long as ovulation occurs. If ovulation occurs on the day of intercourse or at that time, the sperm and the egg can combine quickly to form a fertilized egg, which takes about seven days to implant. After seven days, about 1-2 days after implantation, the patient’s blood chorionic gonadotropin and progesterone levels will rise rapidly. Therefore, patients can tell that they have conceived by checking their blood HCG levels about eight days after intercourse. If the patient ovulates on the second, or third day of intercourse, the patient’s detection of conception will be delayed by 1-2 days. Ten days after intercourse, the patient will be able to tell if she is pregnant by testing her blood HCG levels, and there will be no false-negative results.