Low progesterone is related to the quality of the embryo, which may cause miscarriage, developmental delay and preterm labor. 1. Developmental delay: low progesterone will cause the growth and development of the embryo to be adversely affected, which will lead to lower than normal growth and development of the fetus, and may even cause fetal arrest. 2. Miscarriage: low progesterone is not an indicator of embryo survival. However, if low progesterone is combined with luteal insufficiency, it may lead to miscarriage, and you need to actively undergo fertility preservation treatment. 3. Preterm labor: low progesterone will lead to the sensitivity of the uterus as well as the excitability of the uterus is reduced during pregnancy, and then can not inhibit the excitability of the uterus, resulting in preterm labor. Low progesterone is harmful, and it is recommended that pregnant women go to the obstetrics and gynecology department of a regular hospital as soon as possible to receive examination and treatment.