Delivery of twins at 34 weeks is preterm. Defining twins is whether two babies share one amniotic cavity and one placenta, which determines the time and number of prenatal visits, the risk and chances of complications, and also the way and time of delivery. The details are as follows: 1. If two babies have two separate amniotic chambers, each with a separate placenta, such two babies are very safe. These two babies are not terminated until 38 weeks of gestation; 2. If the two babies have different amniotic chambers and share a placenta with different blood supply, twin fetus transfusion syndrome can occur. If the two babies have different proportions of placenta, selective twin growth restriction will occur. If there is no abnormality during the pregnancy, the pregnancy will be terminated at 37 weeks of gestation; 3. If two babies, sharing one amniotic cavity share one placenta, as the gestational weeks increase, the space of the uterus will become smaller and narrower, and the umbilical cord will be entangled inside, i.e., they may fight. To be safe, terminate the pregnancy at 32 weeks of gestation.