The progesterone test is used to determine if the fetus is in a stable phase, when a blood test for progesterone can be taken as soon as 30 days after the pregnancy is confirmed, without any time limit. Also, when there is abdominal pain, including bleeding, there is no time limit and a progesterone test can be performed at any time. Usually, in early pregnancy, the progesterone level will be around 30 mmol/L. If there is a persistent low progesterone level, it indicates the possibility of preterm miscarriage and, depending on the results of the test, prophylactic fertility treatment should be administered. However, if the progesterone level is below 10mmol/L or 15mmol/L, there is a possibility of ectopic pregnancy, which should be combined with HCG to determine the presence of ectopic pregnancy. At a later stage, it is necessary to determine whether there are bilateral adnexal masses in combination with ultrasound, and in this case, fertility treatment should not be carried out first, but only after intrauterine pregnancy is confirmed.