The application of heparin in pregnant women is mainly to prevent habitual abortion, increase the blood circulation of the placenta to nourish the fetus, play a role in protecting the fetus, but also to prevent thrombosis and anticoagulant treatment during pregnancy. To avoid all kinds of complications caused by shallow placenta, it is suggested to pay attention to the regular medication under the guidance of doctors. Early pregnancy has a history of preterm delivery can be timely heparin, can prevent the occurrence of miscarriage. At the same time, pregnant women are advised to pay attention to rest, with other drugs to protect the pregnancy.