单项超声测量指标预测胎儿体重的临床应用

目的：探讨应用胎儿腹围单项超声测量指标预测胎儿出生体重的临床价值。方法：（１）应用Ｂ型超声对３００例胎儿的腹围、小脑横径、双顶径、股骨长进行测量，并与新生儿出生体重的关系进行分析。经单元线性回归得出腹围预测胎儿体重的单元方程式。（２）应用此方程对３３０例胎儿进行前瞻性验证。结果：腹围与新生儿体重的相关性最好，（ｒ＝０．８６６７９）。依据腹围可以初步预测胎儿出生的体重范围。其符合率达８０．０％。结论：应用超声测量胎儿腹围预测出生体重，方法简单，且较准确，有较好的临床实用价值。     

Review: Trends in Fetal Assessment

Summary: Progress in methods of fetal assessment in late pregnancy has been reviewed by analyzing the papers on this subject in 4 obstetrical journals in 1975. Among 107 papers on fetal assessment, the most common subjects were phospho-lipid assays for fetal lung maturity, antenatal fetal heart rate measurements, ultrasonic studies, and oestrogen assays. The lecitbin/sphingomyelin ratio test has become established as the best currently available measure of functional fetal maturity. Antenatal fetal heart monitoring, with or without oxytocin infusion, is a valuable means of identifying the fetus at risk in late pregnancy.     

Fetal liver measurements by ultrasonography

A total of 378 measurements of fetal liver size were made from 18 weeks gestation through term. Statistical analysis of the results showed a highly significant correlation between fetal liver measurements and gestational age, biparietal diameter, and fetal femur length (R = 0.93, R = 0.89, R = 0.89, respectively). Ultrasonic measurement of the fetal liver is a reliable indicator of fetal growth in the third trimester, as growth rates of the biparietal diameter and head circumference are blunt. Furthermore, consecutive measurements of fetal liver size enhance the detection of symmetrical, fetal growth, by acquisition of various ultrasonic parameters such as biparietal diameter, fetal femur length, fetal abdominal circumference and so forth.     

Fetal ascites in the ultrasound B image

Fetal ascites is a rare ultrasonic diagnosis. The prognostic consequence is not clear. The course of pregnancy with fetal ascites in three cases is represented and compared with literature. The reason of fetal ascites often cannot be determined in spite of extensive diagnostic action. Problems of abortion are discussed.     

Fetal growth retardation in the second trimester.

Growth of the fetal head was assessed by serial ultrasonic measurements in a prospective study of a randomly selected group of 126 mothers. Three cases exhibiting second trimester fetal head growth retardation with varying degrees of catch-up growth before term are illustrated.     

Ultrasound Fetal Weight Estimation: Precision or Guess Work?

Summary: We compared the prediction of birth-weight based on factors shown by epidemiological studies to influence it with the performance of 2 clinical examples of ultrasonic fetal weight estimation reported in the literature. The standardized absolute error of the 2 examples of ultrasonic fetal weight estimation was similar to estimation by multiple regression of birth-weight on maternal age, parity, height and weight in 11,516 Chinese mothers. This severely limits the clinical utility of the estimation derived from these ultrasonic measurements.     

Routine Fetal Maturity Estimation by Ultrasound

The accuracy of ultrasonic estimation of fetal maturity and, therefore, the delivery date is greatest when the biparietal diameteris less than 5.0 cm and least when it is greater than 9.0 cm. A comparison of the accuracy of ultrasonic and last menstrual period based estimations of the delivery date revealed that there is no significant increase in accuracy for ultrasonic estimations when the biparietal diameter is less than 9.0 cm, but when the diameter is greater than 9.0 cm the accuracy of delivery date estimation is significantly less than that based on the last menstrual period. In pregnancies complicated by uncertain dates, recent hormonal contraception, bleeding in early pregnancy, or an irregular or prolonged menstrual cycle, ultrasound is significantly more accurate in predicting the delivery date. Ultrasonic examination for fetal maturity is indicated only when there are clinical indications such as uncertain dates for some reason or when there is fundal height discrepancy.     

Fetal outcome in obstetric cholestasis

Summary. Obstetric cholestasis has been associated with a high incidence of stillbirth and perinatal complications. Between 1975 and 1984, 83 pregnancies were complicated by cholestasis. Meconium staining occurred in 45%, spontaneous preterm labour in 44%, and intrapartum fetal distress in 22%. Of 86 infants two were stillborn and one died soon after birth. Perinatal mortality fell from 107 in a previous series from this hospital (1965–1974) to 35/1000 in this series. Cardiotocography, estimations of oestriol, liver function tests and ultrasonic assessment of amniotic fluid volume failed to predict fetal compromise, whereas amniocentesis revealed meconium in 8 of 26 pregnancies. Early intervention was indicated in 49 pregnancies, 12 because of fetal compromise. This study suggests that intensive fetal surveillance, including amniocentesis for meconium, and induction of labour at term or with a mature lecithin/sphyngomyelin ratio, may reduce the stillbirth rate in this 'high-risk' condition.     

Fetal outcome in obstetric cholestasis

Obstetric cholestasis has been associated with a high incidence of stillbirth and perinatal complications. Between 1975 and 1984, 83 pregnancies were complicated by cholestasis. Meconium staining occurred in 45%, spontaneous preterm labour in 44%, and intrapartum fetal distress in 22%. Of 86 infants two were stillborn and one died soon after birth. Perinatal mortality fell from 107 in a previous series from this hospital (1965-1974) to 35/1000 in this series. Cardiotocography, estimations of oestriol, liver function tests and ultrasonic assessment of amniotic fluid volume failed to predict fetal compromise, whereas amniocentesis revealed meconium in 8 of 26 pregnancies. Early intervention was indicated in 49 pregnancies, 12 because of fetal compromise. This study suggests that intensive fetal surveillance, including amniocentesis for meconium, and induction of labour at term or with a mature lecithin/sphyngomyelin ratio, may reduce the stillbirth rate in this 'high-risk' condition.     

Fetal foot length: relationship to menstrual age and fetal measurements in the second trimester

The purpose of this study was to describe the ultrasonic measurement of fetal foot length and to develop mathematical models to quantify the relationships between menstrual age and commonly measured fetal structures. We evaluated 120 patients with known last menstrual periods and normal pregnancies to develop a cross-sectional study population. All patients had ultrasonic measurement of the fetal foot length, biparietal diameter, head circumference, abdominal circumference, and femur length. Least-squares estimation of linear models was used to select the best mathematical models to describe the relationship between menstrual age and fetal foot length. A similar evaluation of the relationship between fetal foot length and the other measured parameters was performed. All models were best described by a linear equation. An R2 value of 0.94, with a standard error of the estimate of 0.204, was obtained for menstrual age versus fetal foot length. When the model for fetal foot length and menstrual age was compared with published anatomical data, close agreement was seen over the time interval studied. Our results suggest that the measurement of fetal foot length with ultrasound gives a reliable assessment of anatomical fetal or neonatal foot length and is highly correlated to the menstrual age of the fetus.     

Fetal blood flow in diabetic pregnancy

Forty pregnant diabetic women were examined with combined Doppler and real-time ultrasound. The volume blood flow in the fetal aorta and umbilical vein was higher and the pulsatility index (PI) in the aorta lower in the early third trimester, as compared with a reference group. Near term, the umbilical artery PI was higher in diabetic than in non-diabetic pregnancies, indicating a higher placental vascular resistance in the former group. The high umbilical artery PI occurred in fetuses who later developed distress in labor. Therefore, a high umbilical artery PI cannot be considered characteristic of diabetic pregnancy, although fetal distress might be more common in diabetic pregnancy. In addition, a high aortic volume flow was found in those fetuses who later develop distress in labor. This might be an expression of an early compensatory mechanism for increased placental vascular resistance. No specific flow variation was observed for any White class, or in association with hypertension or non-optimally regulated diabetes. The blood flow variables in growth-accelerated fetuses were comparable to those found in fetuses with normal weight. Since fetal distress might be more common in diabetic pregnancy, ultrasonic fetal blood flow measurements are recommended for antenatal fetal surveillance.     

Fetal Brain Death Syndrome: A Case Report and Literature Review

Summary: This case describes a new feature of fetal brain death syndrome, abnormal movements mimicking fetal convulsions being subsequently found to be decerebrate hypertonicity in a brain-dead fetus. It also confirms the diagnostic criteria of fetal brain death, both clinical and ultrasonic. The development of polyhydramnios both prior to and after the presumed neurological event is suggested as an association with the diagnosis of fetal brain death. Increased awareness of this event and the heterogeneity of the presentation may prevent further unnecessary Caesarean sections, as to date only 4 of the 10 cases in the literature were diagnosed prenatally. Utilization of techniques such as fetal blood sampling should be considered to further delineate the diagnosis.     

Fetal movements diagnosed by ultrasound in early pregnancy.

The purpose of this work was to ascertain whether ultrasonic techniques based on fetal movements were suitable for examinations in early pregnancy. The series consisted of 124 patients who came to be examined because of bleeding on the 6th-20th gestational week. The rapid B-scan method detected the fetal movements from the 8th week onwards, and the results were 100% reliable from the 10th week onwards. The combined A-B-scan method detected the fetal movements from the 12th week. Techniques based on the detection of fetal heart function were used as control methods. According to our results, the methods based on the indication of fetal movements constitute a practical alternative for elucidating the problems of early pregnancy.     

Fetal skin biopsy in prenatal diagnosis of some genodermatoses

Various methods of obtaining fetal skin for prenatal diagnosis of certain autosomal-recessive congenital genodermatoses have been assessed. An attempt was made to obtain fetal skin by fetoscopy in 15 patients prior to pregnancy termination for a variety of medical reasons at 18-26 weeks. Specimens were obtained only in five cases (8 successful attempts out of 48). In twelve cases, of which five had a history of a child with junctional (Herlitz type) or dystrophic (Hallopeau-Siemens type) epidermolysis bullosa or non-bullous congenital ichthyosiform erythroderma at 16-25 weeks of pregnancy, fetal skin was obtained without fetoscopy under direct ultrasonic control. Specimens were obtained in all cases (33 successful attempts out of 39). In three cases, fetal pathology was diagnosed by the method of semi-thin and ultra-thin skin sections, and the respective pregnancies were terminated.     

A Comparison of the Fetal Femur Length and Biparietal Diameter in Predicting Gestational Age in the Third Trimester

Summary: Using 2 published normograms relating ultrasonic fetal femur length and gestational age, the accuracy of predicting gestational age using fetal femur length was compared to that using the biparietal diameter after 28 weeks' gestation in 50 patients. The results showed that ultrasonic feta! femur length was more accurate than the biparietal diameter in predicting gestational age in the third trimester. Ultrasonic fetal femur length provides an additional parameter in assessing gestational age in late pregnancy.     

Fetal extremity kinetics quantified with Doppler ultrasonography

AIMS: To assess the responsive fetal extremity movement to vibro-acoustic stimulation test (VAST). METHODS: The moving velocity of fetal femur was assessed after VAST by pulsed Doppler device. The ultrasonic beam was insonated at a right angle to the fetal femur. The following parameters were determined: limb retreat velocity in accelerative slope (Pk1); limb replenishment velocity in decelerative slope (Pk2); mean flexion to extension velocity; and the response time to VAST. Among 80 normal singleton pregnancies in 33-41 weeks, 68 were weekly evaluated and the others were assessed for two or more times during the study period, for a total of 680 studies of fetal kinetics. RESULTS: The Pk1 declined from 9.6 to 6.26 cm/s; Pk2 decreased from 2.6 to 1.3 cm/s; mean velocity was reduced from 6.0 to 4.25 cm/s; whereas the response time increased from 0.1 to 0.3 s throughout the study period, i.e., fetal response reduces and the response time increases as maturation progresses. CONCLUSION: The pulsed Doppler may assess fetal activity in any body structure. Reflex responses become slow and complex on both the velocity and response time as maturation increases with gestational age. Our observations have resulted in a novel and easy method for the quantitative assessment of fetal reflex reactivity to external stimuli.     

Observations of Fetal Lung Reflectivity Using Real-Time Ultrasound

Summary: The ultrasonic appearance of the fetal lung alters as pregnancy progresses and this is expressed as increased reflectivity to ultrasound. Evidence is presented that demonstrates that these changes can be induced and that they may reflect increasing lung maturity.     

Fetal behavior analyzed by ultrasonic actocardiogram in cases with central nervous system lesions

AIMS: This study examined whether analysis of fetal behavioral states by monitoring fetal heart rate and movement using an actocardiogram (ACG), could provide prognostic information related to fetal central nervous system (CNS) lesions. METHODS: The ACG simultaneously records fetal heart rate (FHR) and fetal movement bursts composed of spikes of ultrasonic Doppler signals. Durations of FHR accelerations and fetal movement bursts were measured manually. Five actocardiographic indices were studied in 12 fetuses with CNS lesions and in 14 normal pregnancies of 28-38 weeks. RESULTS: Severity of the fetal CNS lesions was estimated from the acceleration/burst (A/B) duration ratio, which correlated with the rank of the sonographic fetal functional test in cases with CNS lesions. Severity of a fetal lesion may also be estimated by the regression equation of the A/B duration ratio and behavioral ranking. CONCLUSION: The severity of fetal CNS lesions may be estimated by quantitative analysis of ACG usings the measurement of A/B duration ratio to provide a prognosis. An ACG may demonstrate a loss of CNS control in cases with severe brain damage.     

Fetal hydrothorax and bilateral pulmonary hypoplasia. Ultrasonic diagnosis

Bilateral pulmonary hypoplasia associated with hydrothorax is an unexplained entity. The purpose of this study was to evaluate an ultrasonic diagnostic approach towards this problem. Antenatal screening of pregnancies at risk for fetal hydrothorax, early detection of suspected hypoplasia and active management might afford the fetus adequate pulmonary function to support extra-uterine life.     

Fetal behaviour in growth retardation: its relationship to fetal blood flow

The fetal behaviour of asymmetrical growth retarded fetuses was compared with that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and echographic examinations for two consecutive hours at 36-38 weeks of gestation. The distribution of gross fetal body movements, fetal breathing movements and fetal eye movements was analysed during the different fetal heart rate patterns. Furthermore, the incidence and organization of fetal behavioural states was investigated. The degree of vascular peripheral resistance was also evaluated by means of pulsed doppler ultrasonic equipment. Growth retarded fetuses were divided into two groups on the basis of the presence or absence of end diastolic flow in the fetal thoracic descending aorta. Growth retarded fetuses showed a delay in the integration of behavioural patterns and a lower coincidence of behavioural states. These findings are particularly evident in the fetuses with a severe increase of peripheral vascular resistance (absence of end diastolic flow in descending aorta). Thus, we suggest that a delay in central nervous system development is present in asymmetrical growth retarded fetuses and that there is a possible relationship of this delay to the degree of peripheral vascular resistance.