Early pregnancy progesterone is less than how much abortion

In the first trimester of pregnancy, the progesterone value is less than 10 ng/L, the probability of abortion is very high, when the progesterone value is less than 5 ng/L, the probability of abortion is 99%. When the patient has a low progesterone value, it is necessary to take fetal protection measures to prevent spontaneous abortion caused by low progesterone value.