活产双胎出生体重不一致的发生情况及其与不良出生结局的关系

Occurrence of live-born twins with birth weight-discordance and its relationship to the adverse birth outcomes

目的探讨活产双胎儿出生体重不一致的发生情况及其与不良出生结局的关系。方法对2011年1月至2020年12月在广州医科大学附属第三医院出生的4 011对双胎活产儿临床资料进行回顾性分析, 双胎中以出生体重分为出生体重大者和出生体重小者, 按出生体重差异[?BW, ?BW=(大出生体重-小出生体重)/大出生体重×100%]水平分为≤15%组、>15%~20%组、>20%~25%组和>25%组, 比较各组母亲妊娠期及分娩情况和新生儿出生结局差异并分析?BW与不良出生结局的关联性。结果 4 011对双胎活产儿中男4 315名(53.8%), △BW为9(4, 16)%, 出生胎龄为(35.3±2.7)周, 其中△BW≤15%组2 908对(72.5%)、>15%~20%组481对(12.0%)、>20%~25%组281对(7.0%), >25%组341对(8.5%)。以?BW 20%为诊断界值时, 出生体重不一致的发生率为15.5%(622/4 011)。△BW≤15%组自然出生比例较?BW>15%~20%组高[10.5%(288/2 740)比6.3%(29/463), P<0.008 3];△BW>25%组新生儿母亲妊娠期高血压疾病患病率最高[25.5%(87/341)比16.7%(47/281)比17.3%(83/480)比13.8%(400/2 899), 均P<0.008 3]。△BW>25%组出生胎龄更低, 早产率更高(均P<0.05)。4组双胎中出生体重小者的极低出生体重(ELBW)或超低出生体重、小于胎龄和转入新生儿科的发生率差异均有统计学意义(均P<0.05)。多因素分析逐步回归校正了母亲年龄、出生年份、出生方式、性别同异性、母亲妊娠期高血压疾病、出生胎龄等因素后, 较高的?BW与出生体重小者ELBW、小于胎龄和转入新生儿科的高风险均有关(均P<0.05), 线性趋势检验显示呈低至中度正相关关系(r=0.22、0.53、0.21, 均P<0.001)。ROC曲线显示?BW临界值12%~17%能较好地预测上述出生结局风险, 具有较好的灵敏度(0.53~0.78)和特异度(0.72~0.79)。结论出生体重不一致影响着部分活产双胎儿。其对出生体重小者的出生结局造成不良影响, 包括ELBW、小于胎龄、转入新生儿科诊治等, 且随着不一致程度增加呈线性相关趋势。

Objective To investigate the occurrence of live-born twins with birth weight-discordance and its relationship to adverse birth outcomes.Methods A retrospective analysis was performed on 4011 pairs of live-born twins in the Third Affiliated Hospital of Guangzhou Medical University from January 2011 to December 2020.Based on the birth-weight discordance ∆BW,∆BW=(birth-weightbig-birth-weightsmall)/birth-weightbig×100%,twins were divided into 4 groups,including ∆BW≤15%,>15%-20%,>20%-25%,and>25%.The differences in maternal and neonatal outcomes among 4 groups were explored.Then the correlation between∆BW and neonatal adverse outcomes were explored.Results TheΔBW was 9(4,16)%and males were accounted for 53.8%(4315 cases)of 4011 pairs of twins.The gestational age was(35.3±2.7)weeks at birth.There were 2908 pairs(72.5%)of twins with ΔBW≤15%,481 pairs(12.0%)with ΔBW>15%-20%,281 pairs(7.0%)with ΔBW 20%-≤25%,and 341 twin pairs(8.5%)with ΔBW>25%.With ∆BW of 20%as the diagnostic cutoff,the incidence of birth weight discordance was 15.5%(622/4011).The proportion of natural births in the ∆BW≤15%group was higher than that in the ∆BW>15%-20%group(10.5%(288/2740)vs.6.3%(29/463),P<0.0083).The ∆BW>25%group had a significantly higher prevalence of maternal hypertensive disorders during pregnancy than that of the other 3 groups(25.5%(87/341)vs.16.7%(47/281)vs.17.3%(83/480)vs.13.8%(400/2899),all P<0.0083).Univariate analysis found that the ΔBW>25%group had a lower gestational age and a higher rate of preterm birth than the other groups.The rate of extremely low birth weight(ELBW)or very low birth weight(VLBW),small for gestational age(SGA),and transferring to the department of neonatology in the smaller twins were significantly different among the 4 groups(all P<0.05).Multivariate analysis showed that higher degree of birth weight discordance was all positively associated with the rate of ELBW,SGA,and transferring to the department of neonatology in smaller twin,even after adjusting maternal age and gestational hypertension,year of birth,mode of delivery,gender,and gestational age(all P<0.05).Moreover,the Mantel-Haenszel test also indicated that there were significantly low to moderate correlations betweenΔBW and the unfavorable outcomes(r=0.22,0.53,0.21,all P<0.001,respectively).The receiver operating characteristic(ROC)curve found that adverse birth outcomes would be well predicted by birth weight-discordant when the diagnostic cut-off ofΔBW was 12%-17%,with an acceptable sensitivity(0.53-0.78)and a high specificity(0.72-0.79).Conclusions Birth weight discordant is not uncommon in live-born twins,and is associated with adverse outcomes including ELBW,SGA,and transferring to the department of neonatology in the small twins.Besides,the risk is linearly related to the increase ofΔBW.In the future,more researches are needed to explore the underline mechanism and long-term impact of birth weight discordance,to guide the prevention and management.