To determine if circulating levels of maternal syndecan-1, a part of the endothelial glycocalyx, change over gestational weeks 11-13 and if first trimester serum syndecan-1 levels are aberrant in women with adverse pregnancy outcomes vs. controls. Dried blood samples from 300 randomly selected women (100 each from gestational weeks 11, 12, and 13) who delivered at Northwell Health were assessed for syndecan-1 levels. Subjects were segregated by gestational age and maternal weight at the time of blood draw. Gestational age-specific medians were determined by linear regression of median syndecan-1 values vs. gestational age. Multiples of the median (MoMs) = syndecan-1/respective gestational age-specific regressed median. After determining a normal range, we performed a case-control study. Cases (n = 119) were singleton pregnancies with preeclampsia or fetal growth restriction who delivered at 20-36 6/7 weeks with 1st trimester conventional aneuploidy screens; 2 controls (n = 238) per case were identified and assessed. Syndecan-1 levels were determined by ELISA. Data were reported as MoMs and analyzed based on Wilcoxon rank-sum test and Fisher's exact test. A progressive and significant increase in median circulating Sdc1 concentrations was observed from gestational weeks 11-13 (p < 0.001). There was no significant difference in median syndecan-1 MoM values among cases and controls (p = 0.22). However, a subgroup of cases (17.6%) had extreme syndecan-1 values (≤ 0.5MoM) vs. 6.7% of controls (p = 0.003, OR = 3.0). Serum syndecan-1 concentrations significantly increase during gestational weeks 11-13. Extremely low 1st trimester serum syndecan-1 values are associated with an increased risk of adverse pregnancy outcome.
Keywords: Biomarker; Fetal growth restriction; Preeclampsia.