Progesterone 13.9ng/ml is low at around 35 days of pregnancy. Progesterone test value is divided into two kinds of large units and small units, 35 days pregnant progesterone at least more than 20ng/ml or more than 60nmol/l belongs to the normal value, less than these words belong to the low. Progesterone can promote embryonic development in early pregnancy, and can reduce the conductivity and excitability of the uterine muscle to prevent the uterus to expel the embryo, has a better role in preserving the fetus. Low progesterone in early pregnancy can easily lead to symptoms of pre-eclampsia, such as vaginal bleeding or with abdominal pain, generally need to be treated with fertility preservation, such as oral progesterone to supplement the progesterone, the medication must be taken under the guidance of a doctor. In addition, the secretion of progesterone in early pregnancy is pulsatile and fluctuates greatly at different times. If the value of progesterone is low once during pregnancy, it does not indicate that the embryo is not developing well, and you can continue to test under the guidance of your doctor. Abnormal test results, timely consultation and review, to avoid delays in the condition.