The size of the probability of keeping the baby with low progesterone depends on the degree of low progesterone and whether the HCG value is rising or falling. 1. The degree of low progesterone: if the progesterone is lower than 5ng/ml, suggesting ectopic pregnancy or poor embryonic development, the chances of keeping the baby are not great. If the progesterone is more than 10ng/ml, the embryo is generally well developed, and the probability of keeping the baby is greater. 2. HCG value rise or fall: HCG value if every other day rise value is ideal, progesterone value is more than 10ng/ml, this situation ruled out ectopic pregnancy, the chances of keeping the baby are greater. If the HCG value falls every other day and the progesterone value is lower than 5ng/ml, the probability of keeping the baby is lower. Whether or not low progesterone can keep the baby, you need to go to the hospital, early and formal diagnosis and treatment.