Intrapartum sonography for fetal head asynclitism and transverse position: sonographic signs and comparison of diagnostic performance between transvaginal and digital examination

Objective: The primary goal of this study was to determine the ultrasonographic signs of asynclitic and transverse head positioning. In addition, we compared the performance of intrapartum ultrasound to vaginal digital examination. Material & Methods: 150 women were evaluated by 2D transabdominal and translabial ultrasound (US) to detect the asynclitic and deep transverse positions. Transvaginal sterile digital examinations were performed immediately after each intrapartum US assessments, the examinations were repeated at intervals of 45–90 minutes. Examiners were blinded to each other’s findings (clinical or sonographic). Data were reviewed and analyzed by an independent reviewer. Results: The efficacy of digital examination was significantly lower than US evaluation for the detection of either transverse position or asynclitism. The most frequent transverse position was the left one, while the most frequent asynclitism was the anterior one. Conclusions: Digital pelvic examination for detection of fetal head transverse position during labor is inferior to US, especially in the deep transverse positioning, where caput succedaneum occurs and reduces the diagnostic accuracy of vaginal digital examination. The US examination leads to early detection of persistent transverse position allowing for earlier timing and optimal technique for the operative vaginal delivery. We describe two signs for diagnosing asynclitism. The “squint sign” and the “sunset of thalamus and cerebellum signs” are two simple US signs allowing detection of anterior and posterior asynclitism.     

Ultrasonographic placental localization with respect to fetal position in utero

Ultrasonographic localization of the placental site was performed serially throughout pregnancy in 56 primigravidas with anteriorly located placentas. The placenta was found to be located on the right side of the uterus significantly more frequently than at any other site on the anterior uterine wall. Placental position was found to be related to the position of the fetus in utero. The role of placental location in determining the high incidence of the left occiput position at delivery is discussed.     

Intrapartum fetal surveillance

Electronic fetal monitoring (EFM) is the recommended method of intrapartum fetal surveillance for high-risk pregnancies. The cardiotocogram (CTG) trace forms a central piece of documentary evidence in medico-legal cases related to intrapartum hypoxia and birth asphyxia. Cardiotocography was introduced in 1960s as a screening tool with the view to reduce fetal hypoxic brain injury and cerebral palsy rates. However, its positive predictive value for intrapartum fetal hypoxia is as low as 30%, with false positive rate of around 60%. Since its introduction in obstetric practice there has been an increase in intrapartum caesarean section and operative delivery rates, but there has been no demonstrable reduction in occurrence of cerebral palsy or intrapartum fetal deaths. The low specificity of CTG for detection of fetal hypoxia therefore necessitates confirmatory tests such as fetal scalp blood sampling (FBS) or analysis of fetal electrocardiography. The National Institute for Health and Clinical Excellence (NICE) recommends continuous intrapartum fetal monitoring with CTG for high-risk pregnancies and storing the CTG electronically for at least 25 years for medicolegal purposes.It is mandatory that all healthcare professionals who are responsible for the care of women in labour are adequately trained and assessed on pathophysiology of fetal heart rate (FHR) changes in labour to improve interpretation of CTG and avoid adverse maternal and/or fetal outcomes.Confidential enquiries into intrapartum morbidity and deaths have shown that the four main contributors to poor perinatal outcomes are – an inability to interpret CTG by the health professionals, a failure to incorporate the overall clinical condition, a failure to communicate or escalate, and delay in taking appropriate action. In this article we discuss three cases, two of which led to adverse perinatal outcomes. The key learning points and risk management issues relevant to the cases are also discussed.     

Levels of agreement between clinical examination and transabdominal ultrasound evaluation of fetal head position in the second stage of labor

Aim: To compare transvaginal digital examination performed by residents and attending physicians to transabdominal suprapubic ultrasound in the evaluation of fetal head position in the second stage of labor.

Methods: A prospective study was conducted at a tertiary center and included pregnant women at term, with normal singleton cephalic presentation fetuses. All patients had ruptured membranes and were evaluated during the second stage of labor. Fetal head position was assessed consecutively by two clinicians (one resident and one attending physician). Afterwards, transabdominal suprapubic ultrasound was performed by another observer. Examiners were blinded to each other’s findings. Cohen’s kappa test was used to assess the degree of agreement between the evaluation methods.

Results: One-hundred sixty-one women were included. Transvaginal examination was consistent with the ultrasound in 45.0% of cases (95% CI: 37–53%) when the examination was performed by residents (k?=?0.349) and in 67% (95% CI: 60–74%) if the attending physician carried out the evaluation (k?=?0.604). When considering only the anterior positions, the Cohen’s kappa test was 0.426 and 0.709, respectively.

Conclusion: Transabdominal suprapubic ultrasound improved the accuracy of the evaluation of fetal head position, namely when transvaginal digital examination was performed by residents. This may be important especially when instrumental deliveries are considered.     

The significance of intracardiac Doppler sonography in terms of fetal growth retardation

Introduction

The proper function of the fetal heart is indispensable for the fetal development and the normal fetal growth. For prenatal medicine, Doppler sonography offers the possibility of a non-invasive method to examine the fetal cardiovascular function under normal and pathological circumstances. The role of the Doppler sonography is to identify those fetuses who have a high risk factor for developing a pre- or intrapartual asphyxia and therefore have to be delivered promptly. This study aimed at evaluating the clinical value of the intracardiac Doppler sonography (IDS) and at scrutinizing its usefulness during the supervision of the pregnancy of intrauterine growth restricted (IUGR) fetuses.

Materials and methods

In a prospective research at the Medical School of Hanover, fetal IDS was applied to 174 pregnant women between the 21 and 37 weeks of gestation (WG). The e-wave and the a-wave, the E/A ratio, and the TVI (time velocity integral) were measured at the atrioventricular (AV) valves. The PV (peak velocity) as well as the TVI were determined at both the aortic and the pulmonary valve. Normal range curves were compiled for all measured parameters.

Results

Alongside a control group with untroubled gravidity, which consisted of 153 patients, IUGR fetuses, who formed a collective of 21 patients, were Doppler sonographically examined.While the gestational age advanced, an increase of both the e-wave and the a-wave above the AV-valves could be ascertained, which lead to an E/A ratio <1. Above the semilunar valves there was indicated a slight steady increase of the TPV, the PV as well as the TVI. Normal range curves, which largely correspond to those described in the literature, were compiled for the collective of the pregnancies without pathological findings (n = 153). In comparison to the standard collective, there were no significant differences from the collective of the growth restricted fetuses (n = 21).

Conclusion

A temporal informational advantage of pathological intracardiac Doppler values for high risk pregnancies (IUGR) could not be retraced in the examined collective.Doppler sonography traces acute and chronic deficits, which are indicated by hemodynamic changes of the fetus’s blood supply. The clinical importance of IDS as regards dystrophic fetuses has to be ascertained in continuative studies: In the stage of compensatory placental insufficiency (IUGR, arterial Doppler without ARED-flow, venous Doppler without pathological findings) the IDS cannot provide an informational advantage. Contrastingly, the diagnostic potential of the IDS as a screening method of fetal cardiac insufficiency during decompensative placental insufficiency (IUGR, arterial Doppler with ARED-flow, venous Doppler normal or pathological) remains indistinct and should therefore be prospectively evaluated within this high risk group and contrastingly compared to the significance of the venous Doppler sonography (informational advantage?).

     

Intrapartum fetal surveillance

Electronic fetal monitoring (EFM) is the recommended method of intrapartum fetal surveillance for high risk pregnancies. Despite the questions about its efficacy and controversy regarding increased rates of operative delivery associated with its use, continuous cardiotocography (CTG) remains the predominant method of intrapartum fetal monitoring. The CTG trace also forms a central piece of documentary evidence in medico-legal cases related to intrapartum hypoxia and birth asphyxia.Although CTG is sensitive in detecting abnormalities of fetal heart rate (FHR), its specificity for detection of fetal hypoxia remains low and therefore confirmatory tests such as fetal scalp blood sampling (FBS) or analysis of fetal electrocardiography (ECG) become necessary. Due to the rising costs of litigations related to birth asphyxia and increasing complexity of obstetric patient populations, it has become absolutely mandatory that all health professionals responsible for the care of women in labour are trained adequately in interpretation and documentation of CTG traces, as well as the guidelines for actions based on the assessment of the trace and overall clinical situation.Confidential enquiries have always pointed to factors such as inability to interpret traces, failure to incorporate the clinical situation, delay in taking appropriate action and poor team working as contributors to adverse perinatal outcomes. In this article we discuss three case scenarios of adverse maternal and perinatal outcomes due to failure to adhere to basic principles of fetal monitoring and recommended actions as per the national guidelines. The key learning points and risk management issues are also discussed.     

Prenatal diagnosis of bilateral diaphragmatic hernia by fetal sonography

This report describes a case of prenatally diagnosed bilateral diaphragmatic hernia. At 22 weeks' gestation, ultrasound revealed a cystic structure behind the fetus's heart on the axial image at the level of the cardiac four-chamber view. This suggested a left-sided congenital diaphragmatic hernia with herniation of the stomach into the left hemithorax. However, the left-to-right midline shift of the heart was minimal, which is not typical of left-sided congenital diaphragmatic hernia. Throughout the 30th week of gestation, the right and left branches of the pulmonary artery were hypoplastic compared with the values in normal fetuses of the same gestational age. The presumptive diagnosis was bilateral congenital diaphragmatic hernia. A female newborn weighing 2900 g was delivered at 37 weeks' gestation, and she died at 7 h of age. An autopsy revealed large defects on both sides of the diaphragm. In conclusion, prenatal diagnosis of bilateral diaphragmatic hernia is possible with fetal sonography.     

Doppler sonography of the fetal venous circulation

Venous Doppler sonography has been used for assessment of the fetal hemodynamics in the last 15 years. The velocimetries of the central fetal veins — umbilical vein (UV), ductus venosus (DV), hepatic veins (HV) and inferior vena cava (IVC) — reflect the cardiac function and its impairment due to changes in cardiac preload or afterload, and due to changes in the cardiac rhythm. It is possible to see the severity of the disturbance in cardiac function and venous Doppler is broadly used in the surveillance of pregnancies, which are disturbed by severe placental insufficiency, cardiac defects, arrhythmias, anemia, hydrops fetalis and hyper- or hypovolemia as in twin-to-twin transfusion syndrome. Herein we summarize the past, present and eventual future developments of venous Doppler sonography, reflecting the physiology and pathophysiology of the fetal venous circulation and describing the state of the art of its clinical application.     

3D/4D sonography moved prenatal diagnosis of fetal anomalies from the second to the first trimester of pregnancy

The introduction of 3D/4D sonography with high frequency transvaginal transducer has resulted in remarkable progress in ultrasonographic visualization of early embryos and fetuses and development of new fields of 3D sonoembryology. With the proper use of this new diagnostic modality and with experienced examiner, both structural and functional development in the first trimester of gestation can be assessed more objectively and reliable. Indeed new technology moved embryology from postmortem studies to the in vivo environment. Furthermore, there are good reasons to believe that 3D/4D sonography moved prenatal diagnosis of fetal abnormalities from the second to the first trimester of pregnancy. We will try to illustrate it with the number of convincing slides.     

产时电子胎心监护

产时胎儿监护对于保障胎儿分娩期安全、及时发现胎儿宫内缺氧和减少新生儿近远期不良结局的发生至关重要。产时电子胎心监护是国际普遍推荐使用的产时胎儿监护措施。正确掌握产时电子胎心监护的临床应用主要包括胎心率基本波形的定义、胎心率波形的生理病理意义以及针对胎心率波形的临床处理原则3部分内容。文章结合近年来国内外相关指南，对产时电子胎心监护做一阐述。     

Role of fetal echocardiography in stepwise sequential screening for chromosomal disorders (combined test associated with modified genetic sonography)

Objectives: To evaluate the contribution made by fetal echocardiography in identifying Down’s syndrome (DS) and other chromosomal disorders in a stepwise sequential screening method (first step: combined test (CT), second step: modified genetic sonography (MGS) (major malformation and nuchal fold)), for DS in the general population of pregnant women. Methods: Prospective study. During a 5-year study period (July 2005–June 2010) 17,911 pregnant women underwent CTs with MGS (with fetal cardiac morphological evaluation performed by obstetricians in a tertiary hospital) as a screening method for DS. We evaluated the sensitivity and false positive rate (FPR) (95% confidence interval (CI)) of three screening methods for DS and all chromosomal disorders: CT, CT + MGS, and CT + fetal echocardiography. Results: A total of 17,911 cases were analyzed with 67 chromosome disorders and 45 DS cases being found. For DS, the CT sensitivity was 80% (95% CI; 68.3–91.7) (36/45) and 79.1% (95% CI; 69.4–88.8) (53/67) for all chromosome disorders, with a FPR of 4.2% (95% CI; 3.9–4.5) (752/17,866) and 4.1% (95% CI; 3.8–4.4) (735/17,844), respectively. For CT + MSG and CT + fetal echocardiography, the sensitivity for DS was 93.3% (95% CI; 85.9–0.99) (42/45) and 95.5% (95% CI; 90.5–0.99) (64/67) for all chromosome disorders. The FPR for CT + MSG was 4.8% (95% CI; 4.5–5.1) (860/17,866) and 4.6% (95% CI; 4.3–4.9) (836/17,844), respectively. The FPR of CT + fetal echocardiography was 4.4% (95% CI; 4.1–4.7) (792/17,866) for DS screening and 4.3% (95% CI; 4–4.6) (770/17,844) for chromosome abnormality screening. Conclusions: Fetal echocardiography is highly capable of identifying DS and other chromosomal disorders as a part of genetic sonography in stepwise sequential screening.     

Assessment of fetal behavior and general movements by four-dimensional sonography

The aim of this paper was to review the clinical applications of four-dimensional ultrasonography in the assessment of fetal behavior. With the use of a computerized database, articles on three-dimensional ultrasonography were reviewed. Several applications of dynamic three-dimensional ultrasonography have been reported, including imaging of fetal movements, facial expression and fetal hand movements. The importance of the assessment of fetal behavior by four-dimensional sonography is stressed. Four-dimensional sonography seems to be a useful imaging tool for clinical problem solving in perinatology, especially in observing the development of the central nervous system in utero.     

Intrapartum stress and lipid status of term infants: relation to fetal adrenal production of dehydroepiandrosterone sulphate

Objective. Evaluate the effect of acute intrapartum stress on umbilical cord plasma levels of cholesterol, triglyceride and dehydroepiandrosterone sulphate (DS) in term infants.

Methods. Umbilical cord plasma levels of cholesterol, triglyceride and DS were measured in 176 infants that delivered ≥37 weeks' gestation. Eighty-eight infants experienced acute intrapartum stress while the remaining infants were non-stressed controls who were case-matched by gestational age and delivery method.

Results. The umbilical cord plasma levels of cholesterol in the stressed infants (71.7 ± 16.1 mg/dL, mean ± SD) were similar to those of the control infants (70.9 ± 16.0 mg/dL). Triglyceride levels in stressed infants were significantly higher (p = 0.003) than those of control infants. Both stressed and control infants with increased triglyceride levels had normal DS levels; however, those with increased cholesterol levels had reduced umbilical cord plasma levels of DS. Stressed infants with increased cholesterol levels had significantly lower DS levels than control infants (p = 0.008).

Conclusions. Intrapartum stress leads to increased fetal plasma levels of triglycerides; yet, cholesterol levels are usually unaffected. Infants with increased cholesterol levels also have reduced DS levels, suggesting that the rise in cholesterol was due to a reduction in fetal adrenal utilisation of plasma cholesterol as substrate for steroid formation.     

Longitudinal study of fetal behavior by four-dimensional sonography

During the past decades, ultrasonic studies have revealed the fascinating diversity of fetal intrauterine activities. It has been shown that fetal activity occurs far earlier than a mother can register it, in fact as early as the late embryonic period. Analysis of the dynamics of fetal behavior has led to the conclusion that fetal behavioral patterns directly reflect developmental and maturational processes of fetal central nervous system. With 4D sonography it is possible to produce measurable parameters for the assessment of normal neurobehavioral development. There is urgent need for further multicentric studies until a sufficient degree of normative data is available and the predictive validity of specific aspects of fetal neurobehavior to child developmental outcome is better established.     

Intrapartum fetal heart rate monitoring in cases of cytomegalovirus infection

OBJECTIVE: Several studies have shown that abnormal intrapartum fetal heart rate patterns are the results from pre-existing fetal brain damage. We evaluated intrapartum fetal heart rate pattern of cytomegalovirus-infected fetuses and correlated the patterns with neurologic outcomes. STUDY DESIGN: Between 1991 and 2001, there were 20 cytomegalovirus-infected fetuses. We selected 40 fetuses as control subjects that were matched for gestational age and birth weight. Fetal heart rate was interpreted according to the guidelines of the National Institute for Child and Human Development. The incidence of abnormal fetal heart rate pattern and umbilical blood gases were compared between both groups. We also investigated the factors that contributed to abnormal fetal heart rate pattern in the cytomegalovirus group. RESULTS: Nonreassuring fetal heart rate patterns (prolonged deceleration and recurrent late deceleration) were observed in 8 of 20 fetuses (prolonged deceleration, 7 fetuses; recurrent late deceleration, 1 fetus) in the cytomegalovirus group and in 3 of 41 fetuses (prolonged deceleration, 1 fetus; recurrent late deceleration, 2 fetuses) in the control group (P<.05, Fisher test). Baseline fetal heart rate variability was minimal in 4 of the 7 prolonged deceleration cases in the cytomegalovirus group. Umbilical pH <7.1 was found for 1 fetus in the cytomegalovirus group. The average umbilical arterial pH values were similar in both the groups. In the cytomegalovirus group, there were no differences in the incidence of contributing factors between 8 fetuses with abnormal fetal heart rate pattern (prolonged deceleration and recurrent late deceleration) and 8 fetuses with no change. There were 3 fetuses with cerebral palsy: 2 fetuses in the no change group and 1 fetus in the prolonged deceleration group. Antigenemia was positive exclusively in 4 cases with abnormal fetal heart rate pattern (P<.05). CONCLUSION: Cytomegalovirus-infected fetuses are more likely to show abnormal intrapartum fetal heart rate patterns than low-risk control fetuses, which suggests that the perinatal detection of cytomegalovirus is necessary to distinguish hypoxic-ischemic encephalopathy.     

Intrapartum management of nonreassuring fetal heart rate patterns: a randomized controlled trial of fetal pulse oximetry

OBJECTIVE: We tested if fetal pulse oximetry in addition to electronic fetal monitoring (CTG) and scalp blood sampling improves the accuracy of fetal assessment and allows safe reduction of operative deliveries (-50%) and scalp blood sampling (-50%) performed because of nonreassuring fetal status.Study design A randomized controlled trial was conducted in 146 patients with term pregnancies in active labor and abnormal fetal heart rate patterns: 73 had electronic fetal heart rate monitoring (CTG) and fetal scalp blood sampling (control group), 73 had CTG, fetal scalp blood sampling, and continuous fetal pulse oximetry (study group). RESULTS: There was a reduction of -50% in operative deliveries and fetal scalp blood sampling performed because of nonreassuring fetal status in the study group: operative deliveries, study versus control 25/49 (P 相似文献