Estriol is a sex hormone that represents the metabolite of estradiol and estrone in the body and is a natural estrogen found in the urine. The measurement of estriol in the blood can be used by pregnant women to determine the function of the placenta and thus also to better predict the status of the fetus and to be able to monitor the safety of the fetus according to this condition. It is recommended that pregnant women not only undergo regular maternity checkups during pregnancy, but also take the necessary nutrients to keep their bodies as healthy as possible. Supplementation of vitamins and trace elements in the body is also beneficial to the normal development of the fetus and can prevent fetal abortion or early miscarriage due to fetal malnutrition and smoothly pass the whole pregnancy.