At 9 weeks of pregnancy the fetus is about 25mm, the outline of the fetus begins to be gradually clear, the fetal head is larger than the body, the organs begin to gradually differentiate and take shape, and the placenta begins to appear. The embryo is attached to the uterine wall, causing the placenta to not be fully formed. The embryo is not too firmly attached to the uterine wall, and if you are not careful, it may easily cause the embryonic tissue to fall off leading to miscarriage. If you can’t see the fetal bud and fetal heart, it means the embryo is not developing well and you need to cooperate with the doctor for further examination, such as blood sampling to check the blood HCG and progesterone, to confirm whether there is endocrine deficiency that causes the embryo to develop poorly and avoid causing miscarriage. The size of the fetus in the uterine cavity at 9 weeks of pregnancy may vary, as long as the fetal heart and fetal bud are visible, the fetus is basically well developed.