There is no clinical term for the 3rd day of pregnancy, and if it refers to the 3rd day of intercourse, there are usually no abnormal symptoms. At this time, even if the sperm and egg unite to become a fertilized egg, it will take 6-7 days for it to implant in the endometrium and for implantation to occur, and only after implantation can it lead to changes in the levels of various sex hormones and the early pregnancy reaction. If you are a woman with regular menstruation, you can take an early pregnancy test about 15 days after intercourse to determine whether you are pregnant or not. If you go to the hospital to take a blood test for HCG, it can also be done a few days earlier than the urine test. After the initial clarification through blood and urine tests, an ultrasound is performed at 6 weeks of pregnancy to clarify whether the pregnancy is intrauterine and whether a fetal heartbeat or fetal bud appears. Pregnant women usually have nausea, vomiting and other early pregnancy reactions around 42 days of pregnancy, and most of them will disappear automatically around 3 months of pregnancy, during which it is enough to ensure proper rest and normal diet.