Critical evaluation of American categorization of fetal heart rate (FHR) decelerations and three tier classification—Shortcomings, contradictions, remedies and need for debate

Fetal heart rate (FHR) decelerations are the commonest aberrant feature on cardiotocograph (CTG) thus having a major influence on classification ofFHRpatterns into the three tier system. The unexplained paradox of early decelerations (head compression—an invariable phenomenon in labor) being extremely rare [1] should prompt a debate about scientific validity of current categorization. This paper demonstrates that there appear to be major fallacies in the pathophysiological hypothesis (cord compression—baroreceptor mechanism) underpinning of vast majority of (variable?) decelerations. Rapid decelerations during contractions with nadir matching peak of contractions are consistent with “pure” vagal reflex (head compression) rather than result of fetal blood pressure or oxygenation changes from cord compression. Hence, many American authors have reported that the abrupt FHR decelerations attributed to cord compression are actually due to head compression [2-6]. The paper debates if there are major fundamental fallacies in current categorization of FHR decelerations based concomitantly on rate of descent (reflecting putative aetiology?) and time relationship to contractions. Decelerations with consistently early timing (constituting majority) seem to get classed as “variable” because of rapid descent. A distorted unscientific categorization of FHR decelerations could lead to clinically unhelpful three tier classification system. Hence, the current unphysiological classification needs a fresh debate with consideration of alternative models and re-evaluation of clinical studies to test these. Open debate improves patient care and safety. The clue to benign reflex versus hypoxic nature of decelerations seems to be in the timing rather than the rate of descent. Although the likelihood of fetal hypxemia is related to depth and duration ofFHRdecelerations, the cut-offs are likely to be different for early/late/variable decelerations and it seems to be of paramount importance to get this discrimination right for useful visual or computerized system of CTG interpretation.

Association between Fetal Heart Rate Monitoring during Labor and Neonatal Acidosis in Full-Term Newborns: A Retrospective Multicenter Cohort Study

Introduction: Fetal heart rate monitoring during labor is used to study fetal well-being and predict neonatal acidosis of newborn. Fetal heart rate monitoring is analyzed by the obstetrical team and categorized according to the FIGO guidelines. An important limitation of this diagnostic tool is an inter- and intra-observer variability, leading to subjective cardiotocography interpretation and classification. Our objective was to study the association between the categories of fetal heart rate analysis (according to FIGO classification) and neonatal acidosis of full-term newborns. Study design: This is a multicenter retrospective cohort study conducted between 2014 and 2018 in the Grand-Est region. We searched and included retrospectively children hospitalized in a pediatric intensive care unit in one of the participating hospitals with an ICD-10 coding type “P91.6” corresponding to “Hypoxic Ischemic Encephalopathy”. Maternal, pregnancy, delivery, and newborn characteristics were collected and compared by univariate logistic regression with multiple imputation. Odds Ratio and 95% confidence intervals (CI) were calculated using the model and presented. Multiple imputation with m = 100 imputations was tested, using Rubin rules to combine the results. Results: 55 patients were included in the study. Fetal heart rate tracings classified in Category 3 as “pathological” according to FIGO guidelines were significantly associated with an increased risk of severe neonatal acidosis. Late decelerations and bradycardia during labor were associated with severe neonatal acidosis. Conclusion: Severe neonatal acidosis may be suspected by interpretation of fetal heart rate during labor. Fetal bradycardia and late decelerations are predictive of the severity of neonatal acidosis. This study emphasizes the need to screen severe neonatal acidosis and allows the identification of populations most at risk. Repeated team training and upgrading of fetal heart rate study would further reduce the incidence of neonatal acidosis.

Unexplained fetal tachycardia:A case report

BACKGROUND This study aimed to explore the possible etiology and treatment of severe fetal tachycardia in the absence of organic disease and provide a reference for clinical management of severe fetal tachycardia.CASE SUMMARY A 29-year-old pregnant woman,with a gravidity 1 parity 0,presented with a fetal heart rate(FHR)of 243 beats per minute during a routine antenatal examination at 31+2 wk of gestation.Before termination of pregnancy at 38 wk of gestation,the FHR repeatedly showed serious abnormalities,lasting more than 30 min.However,the pregnant woman and the fetus had no clinical symptoms,and repeated examination revealed no organic lesions.The mother and the baby were regularly followed up.CONCLUSION This was a case of severe fetal tachycardia with no organic lesions and management based on clinical experience.

Interpretation of British experts’ illustrations of fetal heart rate (FHR) decelerations by Consultant Obstetricians, registrars and midwives: A prospective study—Reasons for major disagreement with experts and implications for clinical practice

Objective: To test the reproducibility of British experts’ (eFM, K2MS, Gibb and Arulkumaran) [1-3] illustrations of fetal heart rate (FHR) decelerations by trained British Obstetricians and midwives. To analyze reasons for any discrepancies by examining factors relating to the participants, British experts’ descriptions and NICE guidelines [4]. Design: Prospective observational study. Setting: National Health Service (NHS) Hospitals. Participants: 38 Obstetric Consultants, 49 registrars and 45 midwives. Methods: Printed questionnaire. Statistical Analysis: Fisher’s Exact test. Results: This largest study of its kind showed almost unbelievably high disconnect between CTG interpretation by experts and participants. 98% - 100% midwives, 80% - 100% Registrars and 74% - 100% Consultants categorized FHR decelerations differently from the five experts’ illustrations/interpretations (p < 0.0001). Remarkably, the three experts’ illustrations of early (supposedly most benign) decelerations were classed as atypical variable by 56% Consultants, 78% Registrars and 99% midwives and the CTGs as pathological by 85% of the participants. Conclusions: The high degree of disagreement with the experts’ illustrations (p < 0.0001) did not appear to be due to participant factors. The immediate reasons seemed to be the conflicting illustrations and heterogeneity of experts’ descriptions. But most importantly, these appeared to stem from non-standardized ambiguous definitions of FHR decelerations and many intrinsic systemic flaws in the current NICE guidelines [4]. The NICE concept of “true uniform” (identical) early and late decelerations seems biologically implausible (a myth) and no examples can be found. Another myth seems to be that early and late decelerations should be gradual. Only very shallow decelerations will look “gradual” on the British CTG. These systemic flaws lead to dysfunctional CTG interpretation increasing intervention as well as impairing diagnosis of fetal hypoxemia. This is because the vast majority of FHR decelerations fall in a single heterogeneous “variable” group with many further classed as “atypical” (pathological) based on disproven and discredited criteria [5-7]. There is increasing evidence in USA that a system with variable decelerations as the majority is clinically unhelpful because of loss of information [5-9]. In the interest of patient care and safety, open debate is necessary regarding a better way forward. Classification of FHR decelerations based primarily and solely on time relationship to contractions appears more scientific and clinically useful.

The Signal Extraction of Fetal Heart Rate Based on Wavelet Transform and BP Neural Network

This paper briefly introduces the collection and recognition of bio-medical sig nals, designs the method to collect FM signals. A detailed discussion on the sys tem hardware, structure and functions is also given. Under LabWindows/CVI,the ha rdware and the driver do compatible, the hardware equipment work properly active ly. The paper adopts multi threading technology for real-time analysis and make s use of latency time of CPU effectively, expedites program reflect speed, impro ve s the program to perform efficiency. One threading is collecting data; the other threading is analyzing data. Using the method, it is broaden to analyze the sig nal in real-time. Wavelet transform to remove the main interference in the FM a nd by adding time-window to recognize with BP network; Finally the results of c ollecting signals and BP networks are discussed.8 pregnant women’s signals of F M were collected successfully by using the sensor. The correct of BP network rec ognition is about 83.3% by using the above measure.

非Ⅲ级胎监胎心率基线变异消失时长与频率变化规律

目的探索非Ⅲ级胎监胎心率基线变异消失时长与频率变化规律。方法随机选取2020年1月至2023年5月规律产检并住院分娩的宫内单活胎孕妇2000例,依孕期是否有高危因素,分为高危组与低危组。孕28周开始行胎心监护,每天一次直至分娩,观察其基线变异消失时长与频率变化。结果孕28~40^(+6)周胎心率基线变异消失时长中位数:低危组为5.45~12.40 s/次、高危组为5.95~12.00 s/次;频率中位数:低危组为2.00~3.00次/20 min、高危组为2.00~3.00次/20 min。重复测量方差分析示:两组间胎心率基线变异消失时长与频率:时间效应、组间效应、交互效应差异均有统计学意义(P<0.05)。胎心率基线变异消失事件前12 h内:胎心率基线变异消失时长[M(P_(25),P_(75))]低危组为12.40(11.80,13.50)s/次,高危组为12.70(11.80,13.50)s/次;低危组与高危组胎心率基线变异消失频率[M(P_(25),P_(75))]均为4.00(3.00,5.00)次/20 min;重复测量方差分析示:两组间胎心率基线变异消失时长时间效应有统计学意义(P<0.05)。结论非Ⅲ级胎监胎心率基线变异消失是胎儿心率生理不成熟的表现,也受监测临床环境影响,胎儿越危险,其变异消失持续时间越长,当变异消失时长≥10 s/次,频率≥3次/20 min提示胎心率基线变异消失事件,需及时干预。

基于欧氏距离的胎儿监护仪数据异常检测方法

为满足医院对胎儿监护仪数据异常检测的准确性需求,提出基于欧氏距离的医院胎儿监护仪数据异常检测方法。根据医院胎儿监护仪数据异常检测方法,应用超声多普勒检测仪采集胎儿心率信号数据,采用基于自适应滤波的胎儿心率信号去噪方法去除所采集胎儿心率信号噪声成分,将去噪后的胎儿心率信号作为基于欧氏距离法的胎儿心率信号异常识别方法的识别样本,结合欧氏距离法与强分类器,分析去噪后胎儿心率信号与正常胎儿心率信号的虚拟正弦曲线欧氏距离是否大于整定的欧氏距离阈值,将大于阈值的胎儿心率信号样本分类诊断为异常监护数据。该方法通过医院胎儿监护仪采集的胎儿心率信息准确,且异常检测结果有效可信。

胎心仪产品服务体验优化设计策略与实践研究

随着人民对美好生活需求的日益增长,医疗康养产品设计成为设计研究的热点之一。本文以孕期胎心仪为例,对其开展体验优化的应用性设计研究。首先基于对孕妇群体的深度访谈,总结出两类典型用户画像;其后以服务可视化分析,寻找设计机会点,制订设计策略;最后完成胎心仪设计实践。实践表明,采用服务设计理念对胎心仪产品进行创新设计,能够形成具有深层特征的形态语言,完成体验结构的升级,能为相关产品的开发提供有益参考。

胎儿脐血流监测及胎心监护监测在高危妊娠中的预测价值

目的探讨高危妊娠应用胎儿脐血流监测及胎心监护监测的预测价值。方法回顾性分析2021年3月—2023年3月中国人民解放军空军特色医学中心妇产科收治的180例高危妊娠孕妇的临床资料,均开展胎儿脐血流监测和胎心监护监测。根据产前脐血流和胎心的监测结果,将研究对象分为甲组、乙组、丙组、丁组4组。对比4组的分娩指标(剖宫产、胎儿窘迫、脐带缠绕、羊水过少、胎粪污染、新生儿出生1 min内阿氏评分)、脐血流指标[脐动脉血流比值(systolic to diastolic velocity ratio,S/D)、脐动脉阻力指数(resistance index,RI)、脐动脉搏动指数(pulsatility index,PI)]。结果丁组剖宫产(79.17%)、胎儿窘迫(50.00%)、脐带缠绕(50.00%)、羊水过少(70.83%)、胎粪污染(100.00%)的不良分娩情况发生率最高,显著高于甲组、乙组,差异有统计学意义(P<0.05)。甲组新生儿出生1 min内阿氏评分8~10分比例显著高于乙组、丙组、丁组(P<0.05)。乙组和丙组新生儿出生1 min内阿氏评分8~10分比例均高于丁组(P<0.05)。丁组脐动脉血流指标(S/D值、RI、PI)高于甲组、乙组、丙组,差异有统计学意义(P<0.05)。结论对高危妊娠孕妇应用胎儿脐血流监测及胎心监护监测,可对不良妊娠结局提高预测准确性,有助于围产期的治疗与管理,减少不良分娩结局的产生,提高分娩质量。

基于物联网的胎心监护系统在孕晚期羊水量过少孕妇胎儿监测中的应用研究

目的:探讨基于物联网的胎心监护系统在孕晚期羊水量过少孕妇胎儿监测中的应用。方法:将2019年6月—2020年6月商丘市妇幼保健院产科收治的68例孕晚期羊水量过少孕妇设为对照组,将2020年7月—2021年7月收治的70例孕晚期羊水量过少孕妇设为观察组。对照组孕妇采用传统产前监护,观察组孕妇采用基于物联网的胎心监护系统实施监护。比较两组孕妇胎动异常发生率、新生儿无刺激性胎心监护(NST)异常检出率、孕妇不良妊娠结局及孕妇胎心监护满意度。结果:观察组新生儿NST异常检出率高于对照组,差异有统计学意义(U=9.992,P<0.05)。观察组胎动异常发生率比较,差异无统计学意义(χ^(2)=0.032,P>0.05)。观察组新生儿窒息发生率、早产发生率低于对照组,差异有统计学意义(χ^(2)=6.356、2.630,P<0.05);两组产妇不良妊娠结局中中转剖宫产率、新生儿吸入羊水发生率、产后出血发生率、术后感染发生率、新生儿缺血缺氧性脑病发生率比较,差异无统计学意义(χ^(2)=0.708、0.239、0.759、0.183、0.371,P>0.05)。观察组孕妇胎心监护满意度高于对照组,差异有统计学意义(χ^(2)=8.742,P<0.05)。结论:基于物联网的胎心监护系统可有效提高孕晚期羊水量过少孕妇胎儿的监测效果,有效降低孕妇不良妊娠结局发生率,提高孕妇胎心监护满意度。

彩色多普勒血流成像联合胎心监护无负荷试验在孕晚期高危产妇胎儿宫内窘迫诊断中的效能

目的:探讨彩色多普勒血流成像(CDFI)联合胎心监护无负荷试验(NST)在孕晚期高危产妇胎儿宫内窘迫诊断中的效能。方法:回顾性分析2020年8月至2022年8月该院收治的108名孕晚期高危产妇的临床资料,入院后均行CDFI、NST检查,以产后结果为“金标准”,统计CDFI、NST单项及联合检查诊断孕晚期高危产妇发生胎儿宫内窘迫的结果,比较CDFI、NST单项及联合检查诊断孕晚期高危产妇发生胎儿宫内窘迫的效能。结果:产后结果显示,108名孕晚期高危产妇中,39名发生产前胎儿宫内窘迫;CDFI检查结果显示,25名发生产前胎儿宫内窘迫;NST检查结果显示,24名发生产前胎儿宫内窘迫;CDFI联合NST检查结果显示,38名发生产前胎儿宫内窘迫;CDFI、NST检查诊断孕晚期高危产妇发生胎儿宫内窘迫的灵敏度、特异度、准确度、漏诊率、误诊率、阳性预测值、阴性预测值比较,差异均无统计学意义(P>0.05);CDFI联合NST检查诊断孕晚期高危产妇发生胎儿宫内窘迫的灵敏度、准确度均高于二者单项检查,漏诊率低于二者单项检查,差异有统计学意义(P<0.05)。结论:CDFI联合NST检查诊断孕晚期高危产妇发生胎儿宫内窘迫的效能高于二者单项检查。

产时胎心监护结合心理护理在分娩产妇中的应用

目的探讨产时胎心监护结合心理护理在分娩产妇中的应用效果。方法选取2016年11月至2020年11月在我院分娩的产妇126例,随机分为两组各63例。参照组产妇采用常规护理干预,观察组在参照组基础上采用产时胎心监护结合心理护理干预。比较两组的产妇并发症、新生儿1min Apgar评分以及新生儿不良事件。结果观察组产妇的并发症总发生率明显低于参照组,新生儿1min Apgar评分明显高于参照组,新生儿不良事件总发生率明显低于参照组(P<0.05)。结论产时胎心监护结合心理护理在分娩产妇中应用效果显著,可明显提高新生儿1minApgar评分,减少产妇并发症和新生儿不良事件的发生。

胎儿心率采集信号噪声滤波电路设计及仿真

胎心仪使用硅晶传感器对孕妇孕期体内胎儿心率进行无创监测,胎儿心率是一种微弱信号,信噪比低且母体干扰信号强,包含大量与胎儿心率相似的低频信号,都使胎心信号解析十分困难。本文提出了一种应用于单晶片收发模式胎心仪的多级MFB(Multiple Feedback,无限增益多路反馈电路)滤波电路,此电路对微弱的胎心音进行放大和滤波预处理,并使用软件仿真的方法合理选择滤波电路参数,经过滤波预处理的心率信号进入CPU进行自相关算法得到心率数值。最终实验结果表明:经过此多级MFB滤波电路的胎心音信号信噪比高,滤除高频干扰和大部分低频信号的同时有效保留胎儿心脏搏动波形,从而使胎心计探头在胎心30mm范围内能准确的得到胎儿心率,且扬声器播放音频无杂音。

产前四维超声检查在胎儿心脏畸形诊断中的效能

目的:分析产前四维超声检查在胎儿心脏畸形诊断中的效能。方法:回顾性分析2021年6月至2023年12月于该院行产前检查并经产后追踪诊断为胎儿心脏畸形的98例孕妇的临床资料。以产后追踪诊断结果为金标准,比较产前二维、四维超声检查对不同类型胎儿心脏畸形的检出率。结果:98例心脏畸形胎儿中,肺动脉瓣狭窄4例,室间隔缺损37例,单心房2例,右位主动脉弓2例,右心室发育不良2例,三尖瓣闭锁6例,法洛四联症14例,单心室6例,永存左上腔静脉6例,心内膜垫缺损10例,永存动脉干3例,大动脉转位5例,全肺静脉异位引流1例;产前二维、四维超声检查对肺动脉瓣狭窄、单心房、右位主动脉弓、右心室发育不良、三尖瓣闭锁、单心室、永存左上腔静脉、永存动脉干、大动脉转位、全肺静脉异位引流的检出率比较,差异均无统计学意义(P>0.05);产前四维超声检查对室间隔缺损、法洛四联症、心内膜垫缺损的检出率均高于产前二维超声检查,差异有统计学意义(P<0.05)。结论:产前四维超声检查对室间隔缺损、法洛四联症、心内膜垫缺损的检出率均高于产前二维超声检查。

产时胎心监护联合针对性护理干预在分娩中的应用效果

目的:分析产时胎心监护联合针对性护理干预在分娩中的应用效果。方法:选取2021年3月—2023年3月于梧州市妇幼保健院分娩的产妇200例作为研究对象,随机分为观察组与对照组,各100例。对照组采用传统产时护理模式干预,观察组实施产时胎心监护联合针对性护理干预。比较两组新生儿窒息发生情况、阿普加(Apgar)评分及产妇护理满意度。结果:观察组新生儿窒息率低于对照组,差异有统计学意义(P=0.043);观察组新生儿出生1、5、10 min时Apgar评分高于对照组,差异有统计学意义(P<0.05);观察组产妇护理满意度高于对照组,差异有统计学意义(P=0.030)。结论:产时胎心监护联合针对性护理干预可降低新生儿窒息发生率,改善新生儿出生后身体情况,提高产妇护理满意度。

基于场景交互理论的家用胎心仪功能设计研究

通过“场景交互理论”分析家用胎心仪居家使用的环境适应性问题,对家用胎心仪的功能进行设计优化,提升双人监测的操作体验。基于场景交互理论内涵,将居家胎心监测语境下的角色识别细分为核心用户、辅助用户和周边用户,通过角色行为描述,发掘交互摩擦点,得出初级需求指标,通过AHP层级分析法计算,获取重要设计要求,最终从软硬件交互场景中系统性构建家用胎心仪的产品设计方案,为类似家用医疗产品的设计与开发提供借鉴。

Imperative for improvements and international convergence of intrapartum fetal monitoring: A bird's eye view

Intrapartum fetal monitoring has been criticized for the lack of evidence of improvement in fetal outcome despite causing increased operative intervention. Paradoxically, cardiotocography （CTG） has been a major driver for litigation for neonatal neurological injury. This analytical review tries to explore why extensive clinical studies and trials over 50 years have failed to demonstrate or bring about signifcant improvement in intrapartum fetal monitoring. There seems a need for significant reform. International congruence on most aspects of CTG interpretation [defnitions of fetal heart rate （FHR） parameters, CTG recording speed, 3-tier systems, etc .] is highly desirable to facilitate future meaningful clinical studies, evaluation and progress in this field. The FHR changes are non-specific and poor surrogate for fetal well-being. As a compromise for maintaining low false-negative results for fetal acidemia, a high false-positive value may have to be accepted. The need for redefning the place of adjuvant tests of fetal well-being like fetal blood sampling or fetal electrocardiography （ECG） is discussed. The FHR decelerations are often deterministic （center-stage） in CTG interpretation and 3-tier categorization. It is discussed if their scientifc and physiological classifcation （avoiding framing and confirmation biases） may be best based on time relationship to uterine contractions alone. This may provide a more sound foundation which could improve the reliability and further evolution of 3-tier systems. Results of several trials of fetal ECG （STAN） have been inconclusive and a need for a fresh approach or strategy is considered. It is hoped that the long anticipated Computer-aided analysis of CTG will be more objective and reliable （overcome human factors） and will offer valuable support or may eventually replace visual CTG interpretation. In any case, the recording and archiving all CTGs digitally and testing cord blood gases routinely in every delivery would be highly desirable for future research. This would facilitate well designed retrospective studies which can be very informative especially when prospective randomised controlled trials are often diffcult and resource-intensive.

胎儿心脏定量分析技术在中孕晚期正常胎儿心脏结构及功能的研究

目的:用定量分析技术(fetal heart quantification,Fetal HQ),对中孕晚期正常胎儿心脏结构及功能等参数进行初步分析。方法:收集2019年9月至2020年1月,在北京安贞医院母胎医学中心就诊的,妊娠22~27周间的153例正常单胎妊娠胎儿,进行系统超声心动图检查,存储胎儿标准四腔心切面,通过Fetal HQ软件后处理操作计算出心脏整体及左、右心室不同节段的球形指数(sphericity index,SI),左、右心室24节段舒张末期内径及短轴缩短分数(fractional shortening,FS)、左、右心室面积变化率(left and right ventricular area change rate, FAC)及整体纵向应变(global left and right ventricular longitudinal strain,GLS)和LVEF并探讨各参数数据分布情况及与孕周之间的相关性。并进行检查者间和检查者自身的重复性检验。结果:除左心室1~24节段LVEDD及右心室第4~13节段舒张末期内径(right ventricular diastolic diameter, RVED)与孕周(gestational age, GA)呈正相关,且符合正态分布外,其他参数均与GA无相关性,其中右心室面积变化率(the right ventricular area change rate,RVFAC)、左心室短轴缩短分数(the left fractional shortening, LVFS)、右心室短轴缩短分数(the right fractional shortening,RVFS)及第10~17节段LVSI呈正态分布,整体球形指数(the sphericity index,GSI)、左心室面积变化率(the left ventricular area change rate,LVFAC)、LVEF、左心室纵向应变(left ventricular longitudinal strain,LVGS)、右心室纵向应变(right ventricular longitudinal strain,RVGS)、1~24节段右心室球形指数(right ventricular sphericity index,RVSI)、第1~9节段、18~24节段左心室球形指数(left ventricular sphericity index,LVSI)符合非正态分布。各参数观察者自身ICC为GSI:0.89,LVEF:0.79,LVGS:0.83, LVFAC:0.82, RVFAC:0.75, RVGS:0.74;观察者间ICC为GSI:0.83, LVEF:0.75, LVGS:0.78, LVFAC:0.74, RVFAC:0.70, RVGS:0.62。结论:Fetal HQ技术可以分析胎儿心脏整体及左、右心室24节段结构及功能,对了解胎儿心脏发育过程中不同节段的大小、形态、功能随孕周的差异性变化,提供了新的方法。

磺胺甲恶唑对斑马鱼早期生命阶段的发育毒性研究

磺胺甲恶唑(sulfamethoxazole,SMX)作为一种广谱型抗生素,由于大量使用而在各类水体中广泛存在。为研究SMX对斑马鱼(Danio rerio)早期生命阶段的发育毒性,将3 hpf(hours post fertilization,受精后小时数)内的斑马鱼胚胎在不同浓度(空白对照:0μg·L^(-1),S4:4μg·L^(-1),S40:40μg·L^(-1),S400:400μg·L^(-1))的磺胺甲恶唑溶液中暴露至120 hpf,观察统计斑马鱼胚胎的孵化率,仔鱼的死亡率、心率、体长和畸形率等发育参数,并检测斑马鱼体内生长激素(GH)、胰岛素样生长因子(IGF-Ⅰ)含量以及GH/IGF轴相关基因转录水平的变化。结果显示,40μg·L^(-1)和400μg·L^(-1)的SMX暴露会导致斑马鱼死亡率显著升高,体长明显缩短,并且对仔鱼有明显的致畸作用(心包囊肿、脊椎弯曲和尾部畸形等)。SMX暴露对斑马鱼的孵化率未产生显著影响,但会造成胚胎/仔鱼心率下降。此外,在SMX胁迫下,仔鱼体内GH和IGF-Ⅰ水平显著升高。而基因转录分析发现,S4、S40和S400不同处理组SMX暴露下调了gh1(相对表达量:0.30倍、0.17倍和0.10倍)、ghrb(相对表达量:0.74倍、0.36倍和0.39倍)、igf1(相对表达量:0.75倍、0.23倍和0.33倍)和igf1ra(相对表达量:0.49倍、0.22倍和0.72倍)等多个GH/IGF轴相关基因的转录水平,激素水平的变化相较于基因转录水平的变化可能存在滞后性。实验结果表明,SMX暴露对斑马鱼表现出胚胎发育毒性,可能通过减缓心脏搏动以及干扰GH/IGF轴来抑制斑马鱼仔鱼的早期生长。