What urine and blood tests indicate in the context of pregnancy?

In the context of pregnancy, urine and blood tests, such as the human chorionic gonadotropin (hCG) tests, serve primarily to diagnose and confirm pregnancy. The detection of hCG in these tests indicates that a fertilized egg has implanted in the uterus, which is a key early sign of pregnancy. Therefore, these tests provide diagnostic confirmation of pregnancy rather than just probable signs. Probable signs may include physical changes and symptoms observed by a healthcare provider, but the reliable detection of hCG in urine or blood solidifies the pregnancy diagnosis, making option B the correct interpretation of their purpose. They do not inherently monitor fetal development or assess maternal blood type, which are separate considerations in the prenatal care process.