There is usually no placenta at 9 weeks of pregnancy. The placenta lies between the fetus and the mother and is an important organ in maintaining the growth and development of the fetus in the uterus. The placenta is made up of the amniotic and follicular chorionic villi of the fetal part and the fundic meconium of the maternal part. It usually begins to form around the 10th week of pregnancy. The placenta has the functions of maintaining gas exchange between mother and child, supplying nutrients and discharging fetal metabolites, as well as defense, synthesis and immunity. There is usually no placental tissue at 9 weeks of gestation. The placenta begins to form around 10 weeks of pregnancy, and after 12 weeks, fetal ultrasound can clearly see the location and condition of the placenta. Therefore, ultrasound should be performed regularly after 12 weeks of pregnancy to assess the condition of the fetus, placenta, amniotic fluid and umbilical cord. Pregnant women should have regular ultrasound checkups during pregnancy to assess fetal development and the condition of the placenta, and seek prompt medical attention if there is any abnormality, and under the guidance of a physician, carry out examinations and treatments to avoid causing adverse consequences.