Women of reproductive age who meet the inclusion criteria are recruited from the outpatient department of Renji Hospital from November 2022 to December 2023. Subjects fill in the basic information at the outpatient clinic. After being included in the study, peripheral blood is collected before and during the first trimester (< 10 weeks), second trimester (22-24 weeks) and third trimester (32 weeks) to detect 25(OH)D, calcium, phosphorus and PTH levels. B-ultrasound examination is performed before pregnancy to record endometrial thickness, endometrial hemodynamic index (PI, RI and S/D) and uterine arterial hemodynamic index (PI, RI and S/D) during the luteal phase. Data are comprehensively analyzed through questionnaire form filling, laboratory examination, and clinical information records including pregnancy outcomes (final live birth rate, cesarean section rate, pregnancy loss rate, etc.), obstetric complications, and neonatal delivery information.
The objective of this single-center prospective observational study is to clarify the trend of maternal serum 25(OH)D levels before pregnancy and during pregnancy, and to explore the correlation between serum 25(OH)D levels and subsequent pregnancy outcomes of patients with abortion, so as to provide certain scientific evidence for finding the optimal serum level of 25(OH)D and optimal vitamin D supplementation to maintain a healthy pregnancy.