There is no relationship between the rate of doubling of HCG and boy or girl. Placental trophoblast cells secrete human chorionic gonadotropin, which begins to be secreted gradually after pregnancy, and the speed of HCG secretion is related to whether the embryo develops normally or not. In the case of normal embryonic development, in a normal pregnancy, seven days after ovulation, HCG concentration: 5IU/L, nine days HCG concentration: 100IU/L, and then the secretion increases sharply, about every 48 hours doubled, and reaches a peak in the eight to twelve weeks, HCG concentration of 100,000-500,000IU / L, lasted for one to two weeks, and then gradually decline. If there is an abnormality in the development of the embryo, the HCG concentration in early pregnancy is <2500IU/L, and the HCG secretion is gradually decreasing, which suggests that there is a possibility of miscarriage or the embryo stops developing. If the HCG concentration is <600IU/L, it suggests inevitable miscarriage. In ectopic pregnancies, HCG is lower than in normal pregnancies and the multiplication of HCG concentrations is less than 66% within 48 hours. It is recommended that women during pregnancy under the guidance of a medical professional to conduct reasonable and standardized tests.