1. The development of the fetus in one month of pregnancy. During the first month of pregnancy, the fetus is only the size of a sesame seed, but it has begun to differentiate into different organs and tissues. At this time, the fetus develops mainly through the nutrition provided by the mother, and the most important thing during this period is neurological and cardiovascular development. At the same time, the mother also needs to pay attention to nutritional intake and living habits to ensure that the fetus