胎儿脑电图及其定量分析用于产时胎儿窘迫诊断的研究

目的探讨胎儿脑电图(fetal electroencephalogram,FEEG)波形及其定量分析用于产时诊断胎儿窘迫及判断新生儿预后的价值。方法采用自制的经阴道胎儿脑电电极对65例产妇在第一产程末至胎儿娩出前进行FEEG监测,观察脑电图波形变化并进行定量分析;并将胎儿窘迫组(22例)和非胎儿窘迫组(43例)的脑电图波形及定量分析结果进行比较。同时比较胎儿酸中毒组和血气正常组两组的脑电图波形,分析新生儿近期预后与产时FEEG关系。结果(1)应用经阴道直接接触胎儿头皮的脑电电极记录的脑电图与新生儿脑电图特点相似;(2)胎儿窘迫组产时脑电图波形异常率明显高于非胎儿窘迫组(72·7%和9·0%,P<0·05),前者双频指数(bispectral index,BIS)明显降低、95%边缘频率(spectral edge frequency,SEF)明显升高;(3)胎儿酸中毒组与血气正常组相比产时脑电图及其定量分析有显著异常(BIS:48·23±1·98和70·18±0·76,P<0·05;95%SEF:29·02±1·09和14·02±1·69,P<0·01);(4)产时FEEG异常与新生儿不良预后有关。结论(1)自制的经阴道胎儿脑电电极可准确地采集胎儿脑电信号,且不损伤胎儿头皮,是安全、可行的;(2)胎儿脑电波异常可较早的反映胎儿宫内缺氧及酸中毒的状况,并可做为产时胎儿监测的直观指标;(3)产时胎儿脑电图定量分析BIS、95%SEF是反映胎儿和新生儿缺氧及酸中毒的敏感指标。     

Antepartum fetal evaluation by assessment of fetal heart rate and fetal movements

Three antenatal monitoring tests--fetal movement acceleration test (FMAC-test), fetal heart rate-nonstress test (FHR-NST), and daily fetal movement recording (DFMR) were evaluated in 212 high risk pregnant women. While in 196 cases all three tests were normal, in 16 patients one to three tests showed pathological results. In the latter group, there was a significantly higher incidence of perinatal mortality, low Apgar score and growth retardation. Since false positives are known to occur in these tests, at least two should be pathological to warrant delivery in am attempt to prevent fetal death in utero. The sequence in which the pathology appears in the deteriorating fetus is as follows: the first to become non-reactive is the FMAC-test, followed by decreased fetal movements till cessation, and, finally, severe changes in the FHR-NST take place. The importance of this sequence of events is discussed.     

Open fetal surgery for life-threatening fetal malformations

After more than two decades of experimental and clinical work, fetal surgery has become an accepted treatment modality for selected fetuses with life-threatening anomalies. Color Doppler ultrasound and ultrafast fetal magnetic resonance imaging have enhanced the accuracy of prenatal evaluation traditionally made by ultrasound alone. Fetal lung masses associated with hydrops are nearly 100% fatal. These lesions can be resected in utero if they are predominantly solid or multicystic. Thoracoamniotic shunting may be effective in the setting of a single large predominant cyst. Fetuses diagnosed with left congenital diaphragmatic hernia before 26 weeks' gestation with liver herniation and a sonographic right lung to head circumference ratio (LHR) of less than one may benefit from fetal tracheal occlusion. Fetal sacrococcygeal teratoma complicated with placentomegaly, hydrops, or progressive high output heart failure may benefit from in utero resection of the tumor. Although preterm labor still remains the Achilles heel of open fetal surgery, effective tocolysis may, in the future, expand the scope of fetal surgery.     

Decreased fetal activity and fetal heart rate changes after amniocentesis complicated by fetal hemorrhage

A case is described in which amniocentesis caused placental injury, abruptic placenta, and fetal hemorrhage which caused fetal distress. This was primarily manifested by reduction of fetal movements and later by fetal heart rate deceleration. Emergency cesarean section was performed of monitoring the fetus after amniocentesis by assessment of fetal movements is stressed.     

Relation between fetal heart rate accelerations, fetal movements, and fetal breathing movements

The presence of fetal heart rate (FHR) accelerations is considered a sign of fetal well-being. Fetal body and breathing movements, as visualized by real-time ultrasound, were correlated to FHR accelerations in 16 high-risk pregnancies. The association between FHR accelerations (greater than 15 beats/min lasting 15 sec or more) and the different fetal behavioral states is described.     

Maternal and fetal prostaglandins during acute fetal acidosis

Prostaglandins have been detected in high levels in the fetal circulation. These substances are known to cause marked changes in the fetal and uterine circulations. The present study demonstrated an increase in fetal and maternal circulating levels of i prostaglandin F_2α in fetal lambs with acute acidosis. Both levels correlated with the degree of fetal acidosis. No consistent change in levels of i PGE were noted. Prostaglandins may play a role in the pathogenesis of response to fetal stress.     

Transient fetal hypothyroidism due to direct fetal administration of amiodarone for drug resistant fetal tachycardia

Amiodarone, an anti-arrhythmic drug that contains 39% iodine, is rarely known to cause negative effects on fetal thyroid function after gestational exposure, when given orally to a pregnant woman. Two cases of fetal hypothyroidism after gestational exposure to amiodarone by direct fetal intravenous route are described here.     

Examination of fetal cells and cell-free fetal DNA in maternal blood for fetal gender determination

BACKGROUND: To assess applicability of noninvasive methods for prenatal sex determination, both intact fetal cells and cell-free DNA from maternal blood were studied. METHODS: Maternal peripheral blood samples were obtained from 41 women carrying chromosomally normal fetuses and from 3 women with aneuploid fetuses (47,XX,+18; 47,XY,+18 and 47,XY,+21) at 9-22 weeks of gestation. DNA was extracted from the plasma fraction and analyzed by the nested polymerase chain reaction (PCR) using Y chromosome specific primers. After fetal cells were enriched by MACS, fluorescence in situ hybridization (FISH) with chromosome X and Y specific probes was performed to detect XY cells. RESULTS: Although Y-chromosome-specific DNA was detected by PCR analysis in all maternal plasma samples with male fetuses, 26% women bearing female fetuses also gave positive results. By FISH analysis, XY cells were detected in not only 58% of women bearing male fetuses, but also 13% of their counterpoints with female fetuses. CONCLUSIONS: Our findings suggested that consistent results for fetal gender using PCR or FISH cannot be obtained with intact fetal cells and cell-free DNA present in maternal blood and plasma at 9-22 weeks of gestation, despite their apparent abundant presence.     

胎儿生长受限与印痕现象研究进展

胎儿生长受限(FGR)是围生期主要并发症之一,发生原因与妊娠妇女、胎儿及胎盘三种因素有关.研究表明.FGR儿在成人期易患冠心病、高血压、中风、糖尿病、肥胖等疾病,表明很多成年期疾病可能在胎儿发育期就已被编程,这种现象称为印痕现象.胎儿发育时期营养改变能直接或间接影响胎儿各器官系统生长和成熟;胎儿营养改变和宫内糖皮质激素暴露二者可能通过类似途径引起机体内环境长期变化,导致成年疾病风险增加.节俭表型假说、预言适应性反应假说及胎儿胰岛素假说有助于理解印痕现象.瘦素、儿茶酚胺、葡萄糖转运蛋白、胰岛素样生长因子-1、脂联素等可能是印痕现象发生的重要因子.对印痕现象的理解有助于对某些成年期疾病发生的认识,对FGR儿早期临床干预对降低其特定疾病风险系数有重要意义.     

Maternal and fetal inflammatory responses in unexplained fetal death

Objective: The role of intra-amniotic infection in the etiology of fetal death has been proposed. This study was conducted to determine the prevalence of microbial invasion of the amniotic cavity (MIAC) and the frequency of maternal and/or fetal inflammation in patients presenting with a fetal death. Methods: A prospective study was conducted in patients with a fetal death. Amniocenteses were performed for clinical indications (karyotype), as well as to assess the microbiological and cytological state of the amniotic cavity. Fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. An amniotic fluid white blood cell count and glucose determinations were also performed. Histological examination of the placenta was conducted to identify a maternal inflammatory response (acute chorioamnionitis) or a fetal inflammatory response (funisitis). Results: This study included 44 patients with intrauterine fetal death. The median gestational age at diagnosis was 30.1 weeks (range 16.3-40.4 weeks). One patient had documented MIAC (1/44). Acute histological chorioamnionitis was found in 20.9% (9/43), but a fetal inflammatory response was observed in only 2.3% (1/43) of cases. One patient had a positive amniotic fluid culture for Streptococcus agalactiae (group B streptococcus). Conclusion: Histological chorioamnionitis was present in 20.9% of cases, but MIAC could be demonstrated with conventional microbiological techniques in only one case. A fetal inflammatory response was nine times less frequent than a maternal inflammatory response (maternal 20.9% vs. fetal 2.3%, p = 0.008) in cases of fetal death.     

Human fetal bilirubin levels and fetal hemolytic disease.

The development of secondary fetal anemia in association with maternal red blood cell alloimmunization requires hemolysis. In specimens obtained at the time of a clinically indicated cordocentesis, total and direct umbilical venous bilirubin was measured and the indirect umbilical venous bilirubin calculated in 43 antigen-positive and 30 control fetuses. Twenty-two (51%) of the antigen-positive fetuses had or subsequently developed severe anemia (hematocrit less than 30%). Umbilical venous total bilirubin (r = 0.47, p = 0.0008) and direct bilirubin (r = 0.520, p = 0.04) levels each rose with gestation. Indirect bilirubin did not vary significantly with gestation. Bilirubin was unrelated to hemoglobin. In contrast to the control fetuses, umbilical venous total bilirubin for antigen-positive fetuses was inversely related to hemoglobin (r = -0.57, p less than 0.0001) independent of gestational age (r = 0.53, p less than 0.0001) (multiple R of hemoglobin and gestational age for umbilical venous total bilirubin = 0.76, p less than 0.0001). Eighteen of 22 (82%) fetuses in whom anemia developed had an umbilical venous total bilirubin greater than or equal to 97.5 percentile compared with only eight of 21 (38%) fetuses in whom anemia did not develop (p = 0.009). In longitudinal study the umbilical venous total bilirubin frequently rose above normal weeks before the development of anemia. An umbilical venous total bilirubin greater than 3 mg/dl represented the warning line. Fifteen of 16 (94%) fetuses in whom either severe antenatal anemia or significant postnatal hyperbilirubinemia developed had an umbilical venous total bilirubin greater than 3 mg/dl. We conclude that the normal placental capacity for the transport of fetal bilirubin is exceeded in the face of enhanced fetal hemolysis. An elevated fetal bilirubin often precedes the development of antenatal anemia. The antigen-positive fetus with an elevated bilirubin is at high risk to develop anemia antenatally.     

Abnormal fetal heart rate tracings and congenital fetal hypothyroidism

BACKGROUND: Fetal heart rate (FHR) monitoring is commonly used for fetal surveillance. Despite its widespread usage, there is still a disagreement about its value in predicting fetal distress. CASE: A 29-year-old woman in her first pregnancy was admitted for routine follow-up at 38 weeks gestation. The FHR tracing demonstrated severely reduced baseline variability. Due to non-reassuring FHR patterns accompanied by abnormal biophysical profile, the patient was scheduled for urgent Cesarean section. A newborn with congenital absence of the thyroid gland was delivered. CONCLUSION: Severe reduced baseline variability might be an early sign for fetal hypothyroidism. Future research in this area may examine large populations of neonates with thyroid abnormalities in order to determine if abnormal FHR tracing can better predict congenital hypothyroidism.     

Evaluation of fetal movements with ultrasonic Doppler fetal actograph

Fetal movements in each trimester were recorded objectively and continuously with an ultrasonic Doppler actograph that enables simultaneous tracing of fetal heart rate (FHR) and fetal movement (FM). The record with this method was compared with those of the ultrasonic B-mode and M-mode respectively. The onset of FM signal bursts and FHR acceleration was nearly synchronous and the transitory FHR increase associated with FM signal bursts showed a linear amplitude increment along with the progress of gestation. Fetal hiccup movements were recorded from 24 weeks of gestation and lasted between 4.3 minutes and 17 minutes with a rate of 25 to 28 per minute. No FHR acceleration was recognized in such movements. Maternal perception was 67.7% on average of FM signal bursts. Fetal movements in early pregnancy were detected in the 11th week of gestation (CRL 54 mm). Long-term recording of fetal movements was carried out between 9:30 and 17:00 and the alternation of active and resting phases was investigated. The resting phase lasted 20 minutes on average, (range, 10 to 36 minutes). The fetal activity was not influenced by the maternal food intake. It is clinically significant to evaluate the change in fetal movements objectively and continuously.     

The effect of fetal head compression and fetal acidaemia during labour on human fetal cerebral function as measured by the fetal electroencephalogram.

We investigated the effect of head compression and acidaemia during labour in 25 African primigravidae. Evidence that head compression had occurred during labour was confirmed by both clinical and radiological means at the end of a trial of labour. No significant difference could be demonstrated in the quantity of fetal electroencephalogram (EEG) abnormality that occurred in the groups with marked head compression as compared to the groups without marked head compression. Deterioration in the fetal EEG to a flat record known as electrocerebral silence (ECS) was associated with the development of acidaemia. As fetal heart rate (FHR) decelerations appeared the percentage of ECS in the fetal EEG record increased significantly (P less than 0.05), and likewise, as fetal acidaemia developed a highly significant increase in ECS in the fetal EEG was demonstrated (P less than 0.001). We concluded that in the management of trial of labour there was no significant deleterious change in the fetal EEG as a result of head compression, unless fetal acidaemia supervened. However, in the majority of these cases a significant increase in ECS to more than 20 per cent occurred in association with only moderate acidaemia (pH 7.25 to 7.30).     

Antepartum fetal assessment using a fetal biophysical profile score

The application of the fetal biophysical profile score in the management of 2,400 high-risk pregnancies was assessed. The negative predictive value for normal perinatal outcome was not improved compared to single variable tests. The positive predictive value for abnormal perinatal outcome was improved. The overall perinatal mortality in 2,485 fetuses was 9.2 per 1,000. In the 1,980 fetuses with a normal biophysical profile score within 7 days of delivery, excluding lethal anomalies, the perinatal mortality was 1 per 1,000. Fetal movement counting is supported as the most valid and appropriate test for universal fetal screening.