Unfortunately, ectopic pregnancy is not so rare, which threatens a woman with surgery, and in some cases the inability to have children in the future. A fertilized egg can be seen already from the twentieth day of fertilization. More accurate results with a vaginal probe are obtained starting from the 5th week. An empty uterine cavity should be cause for concern, which may mean that a fertilized cell is in the tube. Additionally, blood donation for hCG is prescribed. The percentage of error is so minimal that it is not taken into account.