It is possible for twins to become a single pregnancy, and if one of the embryos stops developing during the course of development it becomes a singleton. An ultrasound at around seven weeks of pregnancy to see the buds will determine whether the pregnancy is twin or single, and twin fetuses increase the risk of pregnancy. If there is an abnormality in the development process, the development may stop and the other embryo will continue to grow. If a twin pregnancy occurs, it is important to have regular checkups, which is more conducive to eugenics. Twin pregnancy should pay attention to nutrition, daily intake of sufficient minerals, proteins, calories, fat, to meet the needs of the growth and development of the two fetuses. Twin pregnancy is prone to gestational hypertension, to the late stages of pregnancy should be a weekly obstetric examination, according to the specific circumstances of pregnant women, the position of the fetus to choose the appropriate mode of delivery, if necessary, can be carried out in advance of the caesarean section.