Reference intervals of systemic immune-inflammation index, neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio during normal pregnancy in China.

The SII, NLR, LMR, and PLR showed dynamic changes during pregnant trimesters. RIs of SII, NLR, LMR, and PLR for healthy pregnant women according to pregnant trimesters and maternal age were established and validated in this study, which will promote the standardization of clinical application.