Serum calcium level at 32 weeks of gestation could be applied as a predictor of preterm delivery: a retrospective study

Abstract Preterm delivery (PTD) leads to severe adverse maternal and neonatal outcomes and larger medical costs. Thus, PTD deserves more attention. However, how to predict PTD is a problem that bothers researcher. This study aimed to investigate potential prenatal predictors of PTD. We retrospectively recruited pregnant women who experienced either PTD or term delivery (TD) and underwent laboratory examinations at 32 weeks of gestation. We compared the test results between the two groups and performed logistic regression analysis and receiver operating characteristic (ROC) curve analysis to identify risk factors and predictive factors for PTD. We found that the PTD group had significantly higher levels of lymphocyte count, mean corpuscular hemoglobin concentration, calcium, uric acid, alkaline phosphatase, triglycerides, and total bile acids. On the other hand, mean corpuscular volume, homocysteine, neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR), neutrophils to (white blood cells - neutrophils) ratio (dNLR), and (neutrophils × monocytes) to lymphocyte ratio (SIRI) were significantly lower in the PTD group. ROC curve analysis revealed that calcium had an area under the curve (AUC) of 0.705, with a cut-off value of 2.215. Logistic regression analysis showed that premature rupture of membranes was an independent risk factor for PTD. Our study demonstrated that serum calcium levels, NLR, dNLR, and other laboratory tests conducted at 32 weeks of gestation can serve as predictors for PTD. Furthermore, we identified premature rupture of membranes as a risk factor for PTD.