Michael Meyenburg

Has diagnostic ultrasound mutagenic effects

SummaryChinese hamster ovary cells were treated with ultrasound from a fetal pulse detector (Eucotone, Siemens) operated at 10 mW/cm2 and 2.2 MHz. The frequencies of structural chromosomal aberrations and of sister chromatid exchanges were not increased by the treatment. There was no indication of single-strand breaks induced by ultrasound in the G2 phase of the cell cycle.

Time Interval in Twin Delivery – The Second Twin Need Not Always Be Born Shortly after the First

In order to evaluate the influence of the time interval on the second twin in twin deliveries, we have used more precise criteria than have been used in the literature to date. The following parameters of the twins were analyzed: normal CTG of the second twin recorded continuously during labor and pH value of the umbilical artery blood after delivery as well as clinical state according to the modified Apgar score. We could not find a general influence of the time interval on pH and clinical status of the second twin. Our results indicate that in cases of uncomplicated twin delivery with a normal cardiotocogram there is no necessity for the second twin to be born as soon as possible after the birth of the first twin.

Postterm pregnancy: computer analysis of the antepartum fetal heart rate patterns

The purpose of this study was to establish reference ranges for numerical fetal heart rate (FHR) data in postterm pregnancy and to compare them with the patterns of fetuses under undisturbed condition at term. FHR was analysed on‐line by Sonicaid Computer System 8000. A statistically significant decrease in the number of accelerations and decrease of variation in postterm pregnancy was observed. The duration of high variation (high episodes) in the 42nd week of gestation was statistically lower than in the pregnancy at term. These observations should be taken into account by clinicians in the interpretation of FHR records in postterm pregnancy.

The effect of maternal oxygen administration on fetal and maternal blood flow values using Doppler ultrasonography

Thirty-one pregnant women divided into three groups (AGA prepartum, SGA prepartum without distress, AGA in labor) were examined using Doppler ultrasonography before, during and after oxygen administration to mothers via a face mask. The aim of the study was to find out if there was any effect on the blood flow values in the fetal aorta, the umbilical artery, the fetal common carotid artery and the uterine arcuate arteries. The resistance index (RI) did not change in those vessels during maternal hyperoxygenation with one exception: in the group of SGA fetuses the RI in the fetal aorta increased significantly. Blood flow velocity and volume blood flow remained unchanged in the fetal aorta during oxygen administration.

Effect of the vibratory acoustic stimulation on fetal heart rate patterns of premature fetuses

The purpose of this study was to examine the heart rate patterns before and after a standardized external vibratory acoustic stimulation in a group of 24 healthy premature fetuses at 32–35 weeks gestational age. FHR was analysed on line by Sonicaid Computer System 8000. A significant increase in the number of accelerations and an increase of variation after stimulus were observed. All other FHR patterns such as baseline, high and low episodes did not change significantly.

The influence of oxygen administration to the mother during labor on the fetal transcutaneously measured carbon-dioxide partial pressure.

The aim of this study was to plot the course of the transcutaneously measured PCO2 (tcPCO2) in the fetus during oxygenation of the mother. In our examination 35 parturients with a suspicious or pathologic CTG were given pure oxygen for 10 minutes at a flow speed of 10 l/min. The fetal tcPCO2 was measured with a TCM 3 measuring device from Radiometer. The measuring temperature was 41 degrees C. The fetal tcPCO2 was 67.2 +/- 3.9 mmHg before the O2 application, during the O2 application it was 67.3 +/- 14.1 mmHg and for the period after the O2 application we found an average measurement of 66.7 +/- 13.9 mmHg. Further we investigated whether, depending on the original levels of the fetal tcPCO2 an O2 application to the mother had a measurable effect on the fetal tcPCO2 levels. The average levels of the tcPCO2 in the fetuses with pathological original levels of greater than or equal to 60 mmHg or with normal levels of less than 60 mmHg did not show any significant differences before, during or after the O2 application. Our own results and reports given in the literature about an increase in the fetal O2 partial pressure during maternal oxygenation lead to the conclusion that in cases with fetal hypoxia, the O2 application to the mother--in addition to other measures for intrauterine reanimation or speedy termination of labor--could be of advantage.

Small for gestational age twins: A retrospective analysis of clinical and acid-base status immediately after delivery

In a retrospective study on 86 twins born between 1971 and 1990, the clinical and acidity status of small for gestational age twins in cases of uncomplicated labor was analysed and compared with the status of appropriate for gestational age twins. No difference was observed in Apgar score and umbilical blood pH between growth retarded and normal twins. The single fact of growth retardation without other factors of risk during labor has no influence on clinical status of small for gestational age twins.

Effect of continuous lumbar epidural anaesthesia during labour on fetal transcutaneous carbon dioxide.

The effect of epidural anaesthesia during labour on fetal transcutaneous carbon dioxide (tcPCO2) was observed on 27 fetuses. Our results show that in the course of epidural anaesthesia there is an increase in fetal tcPCO2. We can see a slight increase even before administering the test dose, while preparatory measures are undertaken for the epidural anaesthesia. After administering the test dose and after giving the main dose there is a further increase in fetal tcPCO2, which continues for up to 30 min after the main dose has been given. The results suggest that it is important to consider any pathological conditions in the fetus, so as to avoid the possibility of additionally endangering the fetus during epidural anaesthesia.

Computer Analysis of the Antepartum Fetal Heart Rate Patterns in the Intrauterine Growth-Retarded Human Fetus Using Sonicaid System 8000

A total of 28 pregnant women with growth-retarded fetuses were studied to examine the antepartum fetal heart rate patterns between 30 and 39 weeks of gestation. Sonicaid Computer System 8000 was used to analyze on line 200 cardiotocograms. We found that there is an increase in the number of accelerations, an increase in variation assessed in beats per minute and in milliseconds, an increase in duration of high episode and a decrease in the number of decelerations.

Does Pulsed-Doppler Ultrasound Have Mutagenic Effects? Application of the Ames Mutagenicity Assay to Test Pulsed-Doppler Equipment

Measurement of fetal blood flow has been accepted using pulsed‐Doppler ultrasound. Until recently, there has been a lack of investigations concerning the potential risks of this method. The possible mutagenic effect of a pulsed‐Doppler system was examined in vitro by applying the Ames test. Tester strains of Salmonella typhimurium indicating point mutations were irradiated (TA 98, TA 100, TA 102, TA 1535, TA 1537, TA 1538). A commercially available duplex system was applied in the experiments emitting an ultrasound beam with a spatial‐peak temporal‐average of 5.2 mW/cm2 and a spatial‐peak temporal‐peak of 117 mW/cm2 at a frequency of 2 MHz. The tester strains were sonicated up to 60 minutes, the bacterial suspension being in direct contact with the transducer surface. The ultrasound‐exposed bacterial suspensions were compared with nonexposed samples. Reference mutagens were used for checking the sensitivity of the system. The results do not indicate any mutagenic effects.