If you have regular menstruation with a cycle of 28-30 days, basically after 35 days of menopause, you will see a very small gestational sac in the uterus through ultrasound examination, and around 40 days, you will see the yolk sac inside the gestational sac through ultrasound examination, which is a normal phenomenon. After pregnancy, due to the large increase of estrogen and progesterone in the body, corresponding clinical symptoms will appear, such as nausea, vomiting or anorexia, drowsiness, dizziness, and some localized breast swelling and pain, which are normal physiological phenomena as pregnancy progresses further. It is normal to see the primitive heart tube pulsating through ultrasound examination at around 49 days of pregnancy.