PAPPA and gestational diabetes: A meta-analysis of 17 studies conducted by Talasaz et al. [31] suggested that low PAPP-A levels in early pregnancy were associated with GDM, reporting a sensitivity of 55% (53–58%) and specificity of 90% (89–90%), with a positive likelihood ratio of 2.48 (0.83–7.36) and negative likelihood ratio of 0.70 (0.45–1.09).