Timeline chart and derivation of the first-trimester case-control and glycosylated fibronectin serial measures analytic populations. *Gestational age during the first trimester was 9.8±1.3 weeks; during the second trimester, gestational age was 24.1±1.8 weeks; during the third trimester, gestational age was 35.6±1.8 weeks. GDM, gestational diabetes mellitus.Rasanen. Fibronectin as a Biomarker in Gestational Diabetes. Obstet Gynecol 2013.