Association of blood parameters in early pregnancy with anemia during late pregnancy: a multicenter cohort study in China.

Background: Low-hemoglobin concentration and anemia are important risk factors for the health and development of women and children. The aim of this study was to investigate the correlation between blood indicators in early pregnancy among non-anemia women and anemia in the third trimester among pregnant women in China with uncomplicated pregnancies >36 weeks.

Methods: This was a multicenter, prospective cohort study. Pregnant women registered at the survey hospitals from May 2019 to December 2020 were included and followed up until delivery and discharge. The predictive value of serum ferritin (SF) and routine blood indexes (platelet count, red blood cell count, hemoglobin level, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration) were analyzed using a receiver operating characteristic (ROC) curve for the occurrence of anemia in the third trimester.

Results: The area under the ROC curve of the first trimester hemoglobin for predicting anemia during late pregnancy (cutoff value 128 g/L, sensitivity 82.3%, specificity 49.6%) and iron deficiency anemia (cutoff value 124 g/L, sensitivity 66.3%, specificity 66.4%) in the third trimester was larger than those of other blood variables.

Conclusions: Hemoglobin levels in the first trimester were significantly better predictors of anemia during the third trimester than the other indices. Our study contributes to the clinical practice of early intervention for anemia, thus taking effective measures to improve maternal and infant outcomes.