Pregnant women diagnosed CH and persistently positive aPL who had no autoimmune disease such as systemic lupus erythematosus, antiphospholipid syndrome were recruited and divided into control group (LDA and LWMH were not used), LDA group (LDA was used) and LDA plus LMWH group (both LDA and LMWH were used) according to whether they use LDA and/or LMWH. The gene discussed is FASLG; the disease is antiphospholipid syndrome.