Hemoglobin levels in the third trimester and adverse pregnancy outcomes / 中华围产医学杂志

ABSTRACT

Objective To investigate the relation between hemoglobin (Hb) levels in the third trimester and associated adverse pregnancy outcomes.Methods A retrospective analysis was conducted on 38 624 singleton gravidas recruited from 21 hospitals in three major cities in China from June 2013 to May 2015.Hb levels of all subjects were determined in the third trimester (≥ 28 weeks).Demographic data and clinical information were collected individually.The recruited gravidas were divided into four groups as followsanemic groupHb ＜110 g/L (n=6 256),control group110 g/L ≤ Hb ＜130 g/L (n=22 484),high-level group130 g/L ≤ Hb ＜150 g/L (n=9 460),and super high-level groupHb ≥ 150 g/L (n=424).One way ANOVA and Chi-square test were used for statistical analysis.Results (1) Compared with the control group,anemic group had significantly higher incidences of preterm labor,low birth weight,neonatal admission and neonatal complications [4.9％ (1 095/22 484) vs 6.9％ (431/6 256),3.1％ (708/22 484) vs 4.3％ (272/6 256),6.2％(1 392/22 484) vs 9.2％ (577/6 256),and 7.7％ (1 741/22 484) vs 10.2％ (640/6 256);x2=930.905,21.360,70.506and 39.837,all P＜0.001];high-level group showed significantly increased incidences of hypertensive disorders of pregnancy and preeclampsia [2.3％ (515/22 484) vs 3.2％ (305/9 460) and 1.4％ (313/22 484) vs 1.7％ (161/9 460);x2=23.203 and 6.072,both P＜0.017],but decreased incidences of preterm labor,neonatal admission and neonatal complications [4.9％ (1 095/22 484) vs 3.7％ (346/9 460),6.2％ (1 392/22 484) vs 5.5％ (517/9 460) and 7.7％ (1 741/22 484) vs 6.7％ (631/9 460);x2=331.947,6.245 and 11.154,all P＜0.017];super high-level group had significantly raised incidences of hypertensive disorders of pregnancy,preeclampsia and low birth weight [2.3％ (515/22 484) vs 4.7％ (20/424),1.4％ (313/22 484) vs 3.5％ (15/424) and 3.1％ (708/22 484) vs 5.2％(20/424);x2=10.742,13.575 and 6.512,all P＜0.017].(2) A concentration gradient analysis was performed to further analyze Hb levels in the third trimester in relation to adverse pregnancy outcomes and the results revealed that with the increase of Hb concentration,the incidences of hypertensive disorders of pregnancy,preeclampsia and low birth weight showed U-shaped distributions,while the incidences of preterm birth,neonatal admission and neonatal complications showed decreasing trends (x2=31.233,16.147,25.618,85.383,97.824 and 68.677,respectively;all P＜0.05).Conclusions Abnormal levels of Hb in the third trimester of pregnancy,including anemia and elevated Hb concentration are related to adverse pregnancy outcomes.