Luteinizing hormone from 31nmol/L to 21nmol/L may be caused by luteal insufficiency, you can take luteinizing hormone capsules and other luteinizing hormone supplements. It may also be a sign of preterm miscarriage, to take birth control treatment, need to be analyzed specifically. 1. luteal insufficiency: luteal insufficiency is a common cause of luteinizing hormone reduction, you can take luteinizing hormone capsules and other progesterone supplements under the guidance of a doctor. The effect of oral progesterone is not good, you can intramuscular injection of progesterone, specific need to follow the doctor’s instructions. 2. Pre-eclampsia: Poor embryonic development or embryonic arrest, ectopic pregnancy can lead to pre-eclampsia and decreased progesterone. It is necessary to combine with the ultrasound examination, take appropriate measures to protect the fetus. Luteinizing hormone from 31nmol / L to 21nmol / L, to communicate with the doctor in time, for systematic examination, clear the cause of the disease and then symptomatic treatment. Do not take medication without authorization, so as not to delay the best time for treatment.