Prospective Study of BMD and Ca-P Metabolism in RSA Patients: LMWH Use Versus Control

Inclusion Criteria:

• Age between 18 to 45 years.
• Female who needs to prepare for pregnancy or have a confirmed pregnancy
• normal karyotype of chromosomes.
• normal uterine anatomy under pelvic ultrasound examination.
• Cooperation in completing blood sample collection, testing and ultrasound examination.
• no serious medical or surgical comorbidities.
• Sign the informed consent form.

Exclusion Criteria:

• Presence of diseases affecting calcium metabolism, including primaryhyperparathyroidism, Cushing's disease, chronic liver, kidney and gastrointestinal (e.g., celiac disease) disorders and rheumatoid arthritis.
• Known HIV positive and / or screening visit, HBsAg or HCV antibody positive.
• The malignant tumors occurred in the past 5 years (except for the skin squamous basalcell carcinoma which has been resected and considered cured). Subjects who developedmalignancies five years ago should provide evidence of remission or cure. Subjectswith a history of cervical cancer who had undergone conization or cure in the past 3years were eligible.
• Patients with a history of chronic infection such as Mycoplasma, chlamydia,Cryptococcus and invasive fungal infection should be discussed with the mainresearchers.
• History of active tuberculosis (TB) or evidence of previous TB infection. Subjectswith a history of potential TB infection should also be excluded, unless there is adocumented evidence that they have completed appropriate anti TB treatment inaccordance with CDC guidelines or local regulations before screening. In addition,subjects were strictly forbidden to have any clinical symptoms / signs of active TB.
• Presence of pregnancy contraindications.