A twin pregnancy is a pregnancy with two fetuses at the same time. The incidence of twin pregnancy varies from country to country, region to region and ethnicity to ethnicity. The incidence of twin and multiple pregnancies can be as high as 24% after the application of ovulation-inducing drugs. Dizygotic twins account for about 70% of pregnancies and are associated with ovulation-promoting drugs and genetic factors, and are formed when two eggs are fertilized separately, so there is a difference between the two fetuses formed. Monozygotic twins account for 30% of pregnancies, which are related to advanced maternal age and are formed when one egg is fertilized and split into two fetuses, so the sex, blood type and appearance of the two fetuses are identical. If a pregnant woman feels that her early pregnancy is heavy, her abdomen is growing faster, she has a family history of twin pregnancies or has received ovulation treatment, she can have an ultrasound examination at the hospital from 7 to 8 weeks after the pregnancy is confirmed. A twin pregnancy carries great risks for both mother and child. For the fetus: the risk of stillbirth (1.23% in 2009, higher than 0.5% in singleton pregnancies), 20% of stillbirths are related to twin birth transfusion syndrome; the incidence of preterm birth is significantly higher, with about 50% of pregnancies being delivered prematurely (10% of which occur before 32 weeks of gestation); the rate of malformations in twin pregnancies is significantly higher than in singleton pregnancies by 4.9%, and intrauterine growth retardation is also likely to occur. For the mother: susceptibility to complications of hyperemesis (3-4 times), hyperhydramnios (10 times), fetal malformations (2-4 times), placenta praevia (1 times), placental abruption, postpartum hemorrhage, abnormal fetal position, etc. Due to the high maternal and fetal complications, pregnant women need to undergo more maternity examinations and monitoring during pregnancy, which objectively causes a burden on the pregnant women themselves and their families, both psychologically and financially. Ultrasound is clinically recommended for twin pregnancies at 11-13+6 weeks of gestation to determine gestational week, chorionic villus count, and risk of Down syndrome. Thereafter, the fetal development is monitored by ultrasound every 4 weeks. However, even regular monitoring does not prevent complications. Mothers-to-be with twins are prone to caloric deficiency, anemia, low calcium, and low proteinemia. Therefore, all kinds of nutrients are more than those needed for singleton babies, and they can eat according to the standard of heavy workload. However, the uterus of multiple pregnancies grows fast, so eating too much at one time may make you feel uncomfortable, so you can eat small and many meals. Twin mothers-to-be need to gain 15.8 to 20.4 kg during pregnancy, just about 4.5 kg more than carrying one child, gaining too much weight too fast will increase the occurrence of complications. Pay attention to nutritional intake and start taking appropriate iron, calcium and folic acid supplements around 20 weeks. After the middle of pregnancy, especially after 30 weeks, bed rest is recommended to improve the blood flow to the uterus and increase the weight of the fetus, and to reduce the intrauterine pressure on the cervix and reduce the incidence of preterm delivery. Before delivery, mothers-to-be with twins should increase bed rest and reduce activity. In case of contractions or vaginal flow, they should be hospitalized. Delivery of uncomplicated twin chorionic villus twins can wait until 37 weeks of gestation, while uncomplicated single chorionic villus twins can wait until 36 weeks of gestation. From the point of view of gestational age, vaginal delivery is currently considered preferable for twin pregnancies <34 weeks.