Biochemical pregnancies are not caused by tubal failure. The exact cause of biochemical pregnancy is unknown and may be related to the woman’s age, the quality of the embryo, and other factors. A biochemical pregnancy, also known as a subclinical abortion, is a pregnancy that occurs when sperm and egg unite to form a fertilized egg, but the fertilized egg does not settle in the uterus and the pregnancy is terminated naturally. An incompetent fallopian tube may prevent the sperm and egg from combining and a pregnancy will not occur, nor will a biochemical pregnancy, which occurs when the tubes are open. Biochemical pregnancy may be related to the woman’s age, egg quality, endometrial status and other factors, while poor sperm quality and chromosomal abnormalities in men can also lead to biochemical pregnancy. Biochemical pregnancies should be treated in a timely manner, and the cause should be clarified under the guidance of the doctor to prevent recurrence of the condition.