The first trimester of pregnancy is a particularly dangerous period, but also a more important period for fetal development. Mothers-to-be should pay attention to their bodies and not worry too much about the most common problem, which is low progesterone, which generally has several aspects. Poor embryo quality will appear low progesterone, sperm or eggs either side if the quality is not up to standard, they will also be unhealthy after the union, will lead to the secretion of human chorionic gonadotropin, which is usually called hcg secretion too little, can not stimulate the corpus luteum to secrete progesterone to help the fetus grow, this situation of low progesterone without the need for birth control, eugenics is the best practice. Low progesterone that occurs with bad luteal function, some people’s own hormones can not stimulate the corpus luteum to secrete enough progesterone, that is, insufficient luteal function, usually we can judge by measuring the basal body temperature, if the luteal phase is less than 12 days or the body temperature climbs more than 3 days to reach high temperature, we can generally judge that the luteal function is bad. Another way is to go to the hospital to check the hormone level during the luteal phase. In this case, external progesterone supplements can be used to help the fetus grow. There is also a situation where some mothers-to-be have low progesterone levels, but the fetus is healthy and no external supplementation is done, just a rest and recuperation bedside method, and the fetus is eventually born without any problems. The medical aspects of the problem sometimes experts can not give an accurate judgment, the mother-to-be need to do is to pay attention to the changes in the body at any time, but at the same time not too worried about thinking, because too much worry will also affect the body’s hormone secretion, but the fetus has a negative impact, although this is difficult, but still hope that the mother-to-be to adjust their mindset, if there are bad changes, it is best to bed rest, follow the doctor’s advice. At the same time, you should cheer yourself and your baby. I believe that our babies are very strong.