高原地区藏族农牧民妊娠晚期血红蛋白水平及其与妊娠结局的相关性

Maternal hemoglobin levels in the third trimester and its correlation with pregnancy outcomes among rural residents in Tibetan Plateau

目的分析高原地区藏族农牧民妊娠晚期血红蛋白(hemoglobin, Hb)水平、贫血状况与海拔高度及妊娠结局的相关性。方法前瞻性收集2020年5月至2021年3月间在西藏自治区昌都市察雅县人民医院就诊, 并于妊娠28周后住院分娩的390例藏族农牧民孕妇的临床和实验室检查资料。研究对象均在入院时及分娩后24~72 h常规使用自动血液分析仪检测血常规。采用世界卫生组织(World Health Organization, WHO)推荐的海拔校正Hb标准, 分析海拔校正前后的妊娠晚期Hb水平、贫血率及其与妊娠结局的关系。采用Mann-WhitneyU检验, 方差分析、χ^(2)检验、Pearson及Spearman相关分析进行统计分析。结果 (1)该地区藏族孕妇妊娠晚期实测的Hb平均水平为(121±16)g/L, 贫血率和小细胞低色素贫血率分别为23.8%(93/390)和20.3%(79/390)。(2)用WHO标准校正后, 孕妇的Hb平均水平为(93±17)g/L, 贫血率和小细胞低色素贫血率分别为84.4%(329/390)和30.5%(119/390)。(3)海拔校正前, 孕妇Hb水平随海拔升高有增加的趋势, 在3 000~3 500 m、>3 500~4 000 m及>4 000 m时, 平均Hb水平分别为(118±15)g/L、(119±17)g/L及(124±16)g/L(F趋势=7.38, P=0.007), 而不同海拔高度之间的贫血率及小细胞低色素贫血率差异均无统计学意义(P值均>0.05)。(4)经海拔校正后的孕妇Hb水平与海拔高度呈负相关(相关系数为-0.31, P<0.001), 在3 000~3 500 m、>3 500~4 000 m及>4 000 m时, 校正后的平均Hb水平分别为(100±15)g/L、(92±17)g/L及(87±18)g/L(F趋势=30.36, P<0.001), 贫血率随海拔升高而升高(χ^(2)_(趋势)=15.44, P<0.001)。不同海拔高度之间的小细胞低色素贫血率差异无统计学意义(P>0.05)。(5)未发现海拔校正前后诊断的妊娠晚期贫血与不良妊娠结局有关, 亦未发现海拔校正前后的孕妇Hb水平与新生儿出生体重相关。结论本地区藏族农牧民孕妇妊娠晚期实测的平均Hb水平随海拔的升高有上升的趋势, 但贫血率及小细胞低色素贫血率仍然较高, 应重视孕期补铁。WHO推荐的海拔校正标准明显增加了妊娠期贫血的诊断率。该标准是否适用于我国高原地区的藏族孕妇仍需进一步研究。

Objective:To study the relationship between maternal hemoglobin concentration,anemia rate in the third trimester and the altitudes,pregnancy outcomes among pregnant women in Tibet rural areas.Methods:This prospective study collected clinical and laboratory data of 390 Tibetan pregnant women who delivered after 28 gestational weeks at Chaya People's Hospital,Changdu city,Tibet autonomous region,from May 2020 to March 2021.Blood routine examination was performed at admission and 24-72 h postpartum using an automatic hematologic analyzer.According to the hemoglobin standard adjusted for altitude by World Health Organization(WHO),the association between pregnancy outcomes and maternal hemoglobin levels and anemia rate before and after adjustment were analyzed using Mann-Whitney U one-way analysis of variance,Chi-square,Pearson correlation,and Spearman correlation tests.Results:(1)In these women,the mean actual hemoglobin concentration in the third trimester was(121±16)g/L,and the prevalence of anemia and microcytic hypochromic anemia was 23.8%(93/390)and 20.3%(79/390),respectively.(2)After adjustment,the mean hemoglobin concentration was(93±17)g/L,and the prevalence of anemia and microcytic hypochromic anemia was 84.4%(329/390)and 30.5%(119/390),respectively.(3)Actual hemoglobin levels showed an increasing tendency as the altitude rose.At the altitude of 3000-3500 m,>3500-4000 m,and>4000 m,the mean hemoglobin levels were(118±15)g/L,(119±17)g/L,and(124±16)g/L,respectively(Ftrend=7.38,P=0.007).However,the prevalence of anemia and microcytic hypochromic anemia did not differ significantly between different altitude(P>0.05).(4)Corrected hemoglobin levels were negatively associated with the altitude(r=-0.31,P<0.001).At the altitude of 3000~3500 m,3500~4000 m and>4000 m,the mean corrected hemoglobin levels were(100±15)g/L,(92±17)g/L,and(87±18)g/L,respectively(Ftrend=30.36,P<0.001).The prevalence of anemia increased with altitude(χ^(2)_(trend)=15.44,P<0.001),but no association was observed between microcytic hypochromic anemia and altitudes(P>0.05).(5)No association was found between actual or corrected anemia in the third trimester and adverse pregnancy outcomes,nor the hemoglobin level before or after adjustment and neonatal birth weight.Conclusions:In Tibet rural areas,the mean actual hemoglobin level in pregnant women tends to increase with the altitude.However,the prevalence of anemia and microcytic hypochromic anemia remains high and more attention should be paid to iron supplementary during pregnancy.After adjusting hemoglobin concentration based on WHO standard,more women were diagnosed as having anemia during pregnancy in this area,and the applicability of the diagnostic criteria for Tibetan residents requires further investigations.