{"id":79,"title":"Gestational Age- and Altitude-Specific Hemoglobin Thresholds and Candidate Windows for Preterm Birth","title_zh":"妊娠期与海拔特异性的血红蛋白阈值及早产风险评估窗口","url":"https://pubmed.ncbi.nlm.nih.gov/42981094","doi":"10.1001/jamanetworkopen.2026.42037","pmid":"42981094","journal":"JAMA Netw Open","kind":"paper","lang":"en","published_at":"2026-11-02T00:00:00+00:00","fetched_at":"2026-11-08T03:43:53+00:00","authors":["Yan G","Ning X","Chen X","Geng L","He P","Xiao T","Wang X","Nong X","Xu J","Yang Y","Wu Y","Zhao Y","Tang S","Huang Y","Bai H","Zhang Y","Qu Z","Tao M","Zhang X","Guo X","Jiang X","Chen S","Liu M","Duan S","Lei H","Li Y","Chen F","Xia W","Lu L","Shu C","Ren Y","Yang J","Huang J","Wang J","Zhang H","Li Y","You D"],"primary_topic":"early-pregnancy","topics":[{"slug":"early-pregnancy","score":4.0,"hits":["preterm birth"]},{"slug":"art-clinical","score":1.0,"hits":["live birth"]},{"slug":"repro-aging","score":1.0,"hits":["maternal age"]}],"topic_score":4.0,"preference_score":0.0,"preference_labels":[],"llm_score":76.0,"final_score":82.0,"score_dims":{"novelty":72,"rigor":86,"impact":70,"relevance":52,"translation":78},"recommend_reason":"样本量大、多中心设计扎实，首次系统给出兼顾孕周与海拔的血红蛋白阈值与评估窗口，对产科早产风险筛查有直接可用性；但属围产流行病学范畴，与ART实验室及胚胎研究的直接关联有限。","keywords":["血红蛋白","早产","海拔","妊娠期特异性阈值","队列研究","产前筛查"],"selected":1,"story_id":210,"llm_provider":"deepseek","llm_model":"deepseek-flash","llm_effort":"low","source_key":"pubmed-art","source_name":"PubMed · 辅助生殖临床","source_tier":1,"mention_count":1,"has_interpretation":false,"journal_key":"jama-netw","journal_tier":"general-top","journal_if":10.5,"is_mock":false,"summary_zh":"该研究基于中国云南5家医疗中心2017—2025年的多源数据库，纳入141 943例单胎活产（早产12 607例，8.88%），采用回顾性队列设计，按每2周孕期分组并结合海拔分层，分析孕前及孕期血红蛋白与早产（含早产亚型）的关联。结果显示血红蛋白与早产呈孕期依赖的U形关联，阈值随孕周变化；高海拔地区阈值普遍更高，孕21周起的低血红蛋白与早产持续相关；医学指征性早产的低血红蛋白关联出现更早，中晚孕期高血红蛋白与两类亚型均相关。作者据此提出按孕周与海拔调整的血红蛋白判读及早产评估窗口，尚待外部验证。","summary":"IMPORTANCE: Maternal hemoglobin is a clinically accessible biomarker of preterm birth (PTB) risk, but abnormal thresholds are inconsistent and do not account for variation by gestational age or altitude. OBJECTIVES: To evaluate the association between maternal hemoglobin concentration and PTB across gestational ages and altitudes, including PTB subtype, and to define gestational age-specific, altitude-adapted hemoglobin thresholds and assessment windows. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, retrospective cohort study used a multisource database integrating electronic medical records, preconception examination, and geospatial data from 5 medical centers in Yunnan, China, a region with a marked altitudinal gradient, and consecutively included singleton pregnancies delivered between January 1, 2017, and July 31, 2025. EXPOSURE: Prepregnancy and prenatal hemoglobin values were assessed. Prenatal measurements were grouped into 2-week intervals (target gestational week ±7 days), with 36 weeks analyzed separately. MAIN OUTCOMES AND MEASURES: Preterm birth was operationally defined as live birth from 28 weeks 0 days through 36 weeks 6 days of gestation. RESULTS: Of 141 943 singleton live births among women (mean [SD] maternal age, 29.7 [4.6] years), 12 607 (8.88%) were PTBs. Maternal hemoglobin measurement showed a gestational age-dependent U-shaped association with PTB, and thresholds varied across gestation. Compared with the intermediate group, a low hemoglobin concentration measured at 13 weeks ( 13.50 g/dL; AOR, 1.28; 95% CI, 1.04-1.55). At high altitude, thresholds were generally higher, and a low hemoglobin concentration from 21 weeks was persistently associated with PTB. Subtype analyses showed earlier low hemoglobin concentration associations for medically indicated PTB and middle- to late-pregnancy high hemoglobin concentration associations for both subtypes. CONCLUSIONS AND RELEVANCE: In this cohort study, hemoglobin thresholds associated with PTB varied across gestation and were generally higher at high altitude; low- and high-hemoglobin assessment windows differed and varied by altitude. These findings may help refine gestational age- and altitude-specific interpretation of routine hemoglobin measurements and PTB risk assessment, pending external validation.","interpretation_basis":null,"fulltext_status":null,"interpretation":null,"fulltext":{"available":false,"status":null,"reason":"尚未抓取全文（未入选、分数未达阈值，或还没跑 fulltext 步骤）","pmcid":null,"license":null,"chars":0,"source":null,"fetched_at":null}}