Placental maturity grade 2 at 29 weeks of pregnancy can be injected with low molecular heparin without relevant drug contraindications. Low molecular heparin drug is a large molecule, it will not cause placental aging or through the placenta to affect the fetus, so placental maturity grade 2 can also be injected with low molecular heparin, which has nothing to do with the maturity of the placenta. If there is any abnormality of D-dimer or problem of coagulation function during pregnancy, heparin can be used under doctor’s instruction, and the dosage of medicine can be strictly controlled. Low molecular heparin can effectively improve the blood coagulation state during pregnancy, which is conducive to the preservation of the fetus, and can prevent the fetus from hypoxia resulting in embryonic arrest. However, if there are relevant contraindications, such as coagulation disorders or gastrointestinal bleeding-related diseases, the use of drugs should be prohibited. If there is any abnormality in the relevant examination, the medication must be used under the guidance of the doctor to avoid the impact on the body, and consult the doctor in time to avoid delaying the condition.