In normal cases of twins, the development of the fetal buds can be observed at 6-7 weeks of pregnancy. The fetal heartbeat of the twins can be observed at 7-8 weeks of pregnancy, i.e. at this time it is possible to completely check if the pregnancy is twin. For women with a regular menstrual cycle of 28-30 days, the initial diagnosis of the fetus can be made by ultrasound examination at 5-6 weeks from the last menstrual period in some women. For women who are pregnant, the time of early pregnancy reaction is also related to the number of fetuses, and most women who are pregnant with a single child have early pregnancy reaction around 45 days of pregnancy. In contrast, for pregnant women with twins, the early pregnancy response can appear around 35 days due to the rapid increase of HCG level in the body. In addition, the twins can be visually observed through ultrasound examination after 45 days of menopause, and the diagnosis of twins can be confirmed if there are two gestational sacs and two fetal hearts. Around 13 weeks of gestation, ultrasound can detect identical twins and clearly show two fetal head halos, and the corresponding spine, trunk, and extremities can be observed. In addition, since twins are clinically considered as high-risk pregnancies, pregnant women are advised to take rest, ensure sleep, stay relaxed, and make prenatal checkups on time and do all prenatal screenings for eugenics.