Pregnancy can be detected by a blood test. When you are pregnant, a fertilized egg will settle in the uterus and the outer cells of the embryo will secrete human chorionic gonadotropin (HCG.) HCG can enter the pregnant woman’s bloodstream, and also passes through the kidneys into the urine. Early pregnancy can be checked by taking a blood test for HCG, or you can purchase test strips from the drugstore to determine if you are pregnant by testing for HCG in your urine. A positive HCG result does not confirm pregnancy, and a combination of ultrasound and other tests is needed to confirm an intrauterine pregnancy. Diagnosis of ectopic pregnancy is mainly made after 40 days of pregnancy, when no gestational sac can be found in the uterine cavity through gynecological ultrasound, and then signs of ectopic pregnancy are found in the pelvis and fallopian tubes and other parts of the uterus, so that ectopic pregnancy can be judged. Pregnancy can be determined by drawing blood for HCG and progesterone levels, combined with ultrasound to check the development of the gestational sac.