Characteristics of long-range monitoring of fetal heart rate in third trimester with atypical non-stress test

目的 研究孕晚期胎心无应激试验(non-stress test,NST)可疑型的长程胎心监护的特点,为NST可疑型的处理提供更加充足的依据. 方法 研究对象为2014年4月至2015年10月在北京大学第三医院建档且规律产前检查,孕36～40周+6,单胎头位,无妊娠合并症、或合并甲状腺疾病但甲状腺功能正常、妊娠期糖尿病单纯饮食控制血糖正常等的孕妇.所有研究对象均知情同意后行长程胎心监护.根据NST结果分为NST可疑型组(36例)和NST反应型组(30例).收集年龄、终止妊娠天数、终止妊娠方式、新生儿窒息率、住院率、超声多普勒脐动脉收缩期最大血流速度与舒张末期血流速度的比值等临床资料,以及通过专门设计的软件分析获得的胎心监护所得数据.采用t检验或x2检验进行统计学分析. 结果 2组孕妇年龄、终止妊娠天数、终止妊娠方式、新生儿窒息率比较,差异均无统计学意义(P值均＞ 0.05).NST可疑型组胎心率基线高于NST反应型组[(138.05±5.65)与(135.10±5.39)次/min,t=-2.170,P＜0.05];而NST可疑型组胎心率基线变异值低于NST反应型组[(5.19±1.07)与(6.28±1.15)次/min,t=3.960,P＜0.001].与NST反应型组比较,NST可疑型组胎心率轻度变异率显著升高[(40.79±9.97)与(51.17±10.84)％],中度变异率显著降低[(56.57±8.86)与(46.72±10.24)％],差异均有统计学意义(t值分别为-4.018和4.133,P值均＜0.001).NST可疑型组的平均胎心加速时长比例和平均单位时间加速面积分别为(37.41±4.60)％和(1.42±0.48) cm2/20 min,均低于NST反应型组[分别为(40.78±4.23)％和(2.03±0.67) cm2/20 min],差异均有统计学意义(t值分别为3.079和4.359,P值均＜0.05). 结论 孕晚期NST可疑型胎儿的长程胎心监护主要表现为胎心基线变异幅度下降、轻度变异率增加和单位时间加速面积减少,但妊娠结局及短期预后与NST反应型胎儿无差异.Objective To analyze the characteristics of long-range monitoring of fetal heart rate in the third trimester fetuses with atypical non-stress test (NST).Methods Long-range monitoring of fetal heart rate was performed in low-risk pregnant women who received antenatal care between April 2014 and October 2015 in Peking University Third Hospital.All subjects underwent NST from the 36th gestational week,and divided into normal NST (30 cases) and atypical NST (36 cases) groups according to the results of NST.The clinical data,including maternal age,gestational age at delivery,termination of pregnancy,neonatal asphyxia,hospitalization rate and umbilical cord blood peak-systolic/diastolic ratio value were collected.The data of long-range monitoring were analyzed by specially designed computer software.T test and Chi-square test were applied for statistical analysis.Results There were no differences in maternal age,gestational age at delivery,mode of delivery and incidence of neonatal asphyxia between the two groups (all P＞0.05).In atypical NST group,fetal heart rate baseline was higher [(138.05±5.65) vs (135.10±5.39) bpm] (t=-2.170,P＜0.05),and fetal heart rate baseline variability was lower than in normal NST group [(5.19±1.07) vs (6.28±1.15) bpm] (t=3.960,P＜0.001).Compared with normal NSTs,the percentage of mild baseline variability was significantly increased in atypical NST group [(40.79±9.97) vs (51.17± 10.84)％],while that of moderate variability was significantly decreased [(56.57±8.86) vs (46.72± 10.24)％] (t=-4.018 and 4.133,both P ＜ 0.001).In atypical NSTs,the average ratio of time of acceleration/the whole time of monitoring [(37.41 ±4.60)％] and acceleration area per unit time[(1.42±0.48) cm2/20 min] were decreased compared with normal NSTs [(40.78±4.23)％ and (2.03±0.67) cm2/20 min] (t=3.079 and 4.359,both P＜0.05).Conclusions Long-range monitoring of fetal heart rate in the third trimester fetuses with atypical NST is characterized by the declined fetal heart rate baseline variability,increased proportion of mild variability and unit time acceleration area;but these are not associated with pregnancy outcomes and short-term prognosis.2014年首都卫生发展科研专项项目; 2014年北京大学第三医院临床重点项目(BYSY2014015)The Special Projects of Health Development Research of Beijing Municipality; Peking University Third Hospital Key Projects of Clinical Medicine中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)12885-8891