Abstract: Objective：To establish the reference intervals for hematologic parameters in antepartum and 24 hours after postpartum in healthy pregnant women, and analyze physiological changes occurring in hematologic parameters. Methods: The samples comprised of healthy pregnant women who had cesarean section at term in Tianjin Central Hospital of Gynecology Obstetrics from Jun. 2015 to Oct. 2015. The blood test results before and after delivery were retrospectively analyzed. Results: The reference intervals obtained before delivery were: RBC, （3.27～4.49）×1012/L; Hb, 93.4～135.3 g/L; HCT, 0.286～0.399; WBC, （5.47～12.34）×109/L; PLT, （113.7～307.0）×109/L. After delivery, RBC count and PLT dropped significantly(P=0.002, P=0.000, respectively), and WBC count increased significantly(P=0.000), Hb and HCT levels remained unchanged, and the value of MCV,MCH, MCHC slightly increased, the percentage of neutrophils and intermediate cells increased significantly(P=0.000), while the percentage of lymphocytes dropped significantly(P=0.000). Conclusions: The reference intervals for Hb concentration and PLT in healthy prgnant women showed some differences with non-pregnant women. Compared with antepartum, the WBC count increased after delivery, while the RBC count and PLT count dropped. The differences observed underscore the need to establish reference values for Chinese women before and after delivery.

Key words: Pregnancy, Cesarean Section, Delivery, Hematologic parameter, Reference interval