Gestation 4 ~ 8 weeks for the embryo, after 8 weeks of gestation for the fetus, 4 weeks the embryo has just bedded, is a gestational sac state, within the tiny germ, four weeks at the end of the disc and the body tip can be recognized, the end of the 8 weeks the embryo is the first human form. At 4 weeks, the embryo has just completed implantation in the uterine wall, it is a gestational sac with tiny germs of about 2mm, it is still an embryo consisting of two layers of tissues, the amniotic cavity has just been formed, and the various organs of the body have not yet developed, at the end of the 4 weeks, the embryonic disk and the body tissues are recognizable, and at the end of the 8 weeks the embryo has taken on its first human form, but all of its organs and parts of the body will be developed from these tissues. It is recommended that after 5 weeks of timely ultrasound examination, pay attention to whether the intrauterine pregnancy, in addition to 4 weeks of pregnancy, the embryonic tissue has just landed, you need to pay attention to avoid strenuous exercise, at the same time you need to refrain from sexual intercourse, so as not to cause preeclampsia, but also in the pregnancy of 12 folic acid supplementation to prevent malformations.