Diabetes, especially when poorly controlled diabetes pregnancy, is very harmful to the pregnant woman and the fetus, mainly including the following: First, to the fetus, diabetes combined pregnancy is prone to miscarriage in early pregnancy, preterm labor in the middle and late pregnancy, easily affecting fetal development, leading to intrauterine developmental distress, prone to various malformations, and also prone to produce huge children. Second, for pregnant women, diabetes combined pregnancy, the mother is prone to complications of amniotic fluid infection, too much or too little amniotic fluid, premature rupture of membranes, placenta praevia, etc., also prone to combined gestational hypertension syndrome, etc., making the risk of pregnancy greatly increased. Third, the newborn, diabetes combined with pregnancy, easy to lead to neonatal hypoglycemia, also easy to aggravate neonatal jaundice, due to genetic susceptibility, the chances of developing diabetes also have increased. Therefore, diabetes combined with pregnancy or gestational diabetes require long-term, strict and good control of blood sugar to reduce pregnancy complications.