ORIGINAL RESEARCH article
Front. Glob. Women’s Health
Sec. Maternal Health
Associations of hemoglobin trajectories and time in target hemoglobin range with adverse pregnancy outcomes: a real-world pregnancy records-based study
Provisionally accepted
- 1Shanghai First Maternity and Infant Hospital Tongji University School of Medicine, Shanghai, China
- 2Department of Obstetrics and Gynecology,Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
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Objective: This study aimed to evaluate associations of hemoglobin trajectories during pregnancy and time spent within clinically recommended hemoglobin ranges (Hb-TITR) with adverse pregnancy outcomes. Methods: A retrospective cohort study was conducted using pregnancy records from Shanghai First Maternity and Infant Hospital (from January 2022 to December 2024), involving 7,653 pregnant women with complete serial hemoglobin measurements. Hemoglobin trajectories were categorized as stable, descending, or ascending. Hb-TITR was calculated based on clinically recommended hemoglobin ranges throughout pregnancy. Logistic regression analyses were performed to determine associations with adverse outcomes, adjusting for maternal age, pre-pregnancy BMI, and gestational age. Results: Among participants, 85.2% exhibited stable hemoglobin trajectories, 10.4% descending, and 4.4% ascending. Descending trajectory was significantly associated with increased risk of composite adverse outcomes (adjusted odds ratio [OR] 3.92; 95% CI, 3.30–4.66) compared with the stable group. Conversely, ascending trajectory showed no significant risk elevation (OR 1.13; 95% CI, 0.83–1.51). Reduced Hb-TITR (<80%) significantly increased the odds of adverse outcomes (OR 1.35; 95% CI, 1.10–1.65), whereas longer Hb-TITR was protective. Descending trajectories notably increased risks of PROM, cesarean section, postpartum hemorrhage, macrosomia, SGA, and LGA infants. Conclusion: Descending hemoglobin trajectories and reduced time spent within recommended hemoglobin ranges during pregnancy were significantly associated with increased risks of adverse maternal and neonatal outcomes, highlighting the importance of monitoring hemoglobin dynamics throughout pregnancy.
Keywords: Hemoglobin trajectory, Adverse pregnancy outcome, Real world, time in target range, Prenatal Care
Received: 12 Aug 2025; Accepted: 04 Nov 2025.
Copyright: © 2025 Zhang, Shen, Zou and Xiang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Gang Zou, zougang@51mch.com
Xinli Xiang, 51747748@qq.com
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