First Trimester Hematological Indices in Gestational Diabetes Mellitus: A Meta-Analysis.

Context: The association between blood parameters and gestational diabetes (GDM) is of renewed interest. Some blood cell parameters are assumed to be associated with GDM.

Objective: This meta-analysis was performed to assess the association of hematological indices in the first trimester of pregnancy and later development of GDM.

Methods: A comprehensive database search, including PubMed, Web of Science, Epistemonikos, Scopus, Scientific Information Database, and Magiran, was conducted to identify potential peer-reviewed publications. The PECO framework was applied to evaluate the eligibility of all included studies. Standardized mean differences (95% CI), were calculated. Additionally, pooled odds ratios, summary estimates of sensitivity and specificity, positive and negative likelihood ratios, and diagnostic odds ratios (DOR) were determined.

Results: The meta-analysis encompassed 33 studies involving a total of 247 107 pregnant women. Compared to control groups, GDM groups exhibited statistically significantly higher hemoglobin levels (standard mean difference: 0.50, 95% CI: 0.39-0.62), red blood cell (RBC) (0.23, 0.15-0.32), and hematocrit (0.44, 0.34-0.55). The pooled adjusted estimate (aOR:1.02, 1.006-1.03) indicated that the hemoglobin levels were significantly associated with an increased risk of GDM. GDM groups had significantly higher platelet count (0.280, 0.16-0.39) and white blood cells (WBC) counts, as well as (0.482, 0.377-0.58), lymphocytes (0.12, 0.025-0.22), neutrophils (0.541:0.404-0.679), and neutrophil-lymphocyte ratio (0.31, 0.20-0.43). In distinguishing women with GDM from the control group, the DOR was found to be 3.21 for the hemoglobin and 2.94 for the mean platelet volume.

Conclusion: Higher levels of RBC, platelet, and WBC counts during the first trimester of pregnancy were observed in women who subsequently developed GDM compared to control groups.