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Biomedical subjects

G Gennser

Publications and source records attributed to G Gennser.

At least 37 records · Page 2Linked to original sources
PubMed1986

Incidence and recurrence rate of abruptio placentae in Sweden.

It is desirable to identify those pregnancies that run an increased risk of abruptio placentae, as this disorder still is associated with a high perinatal mortality. Data were collected from the Swedish nationwide birth registry system on all 894,619 births in Sweden in the period 1973 to 1981. The overall incidence of abruptio placentae was 0.44%, with a perinatal mortality of 20.2% and a cesarean section frequency of 74.6%. The incidence of abruptio placentae was significantly increased in the case of twin birth, male offspring, mothers below 20 years of age, and with every delivery after the second one. A history of abruptio placentae increased the risk of a similar incident in a subsequent pregnancy by 10.2-fold. The frequency of cesarean section in subsequent parturitions remained high (32.1%) even in the absence of reabruptio placentae, thus demonstrating the need to identify further risk groups.

Abruptio Placentae↗
PubMed1984

Physiological characteristics of diameter pulses in the fetal descending aorta.

A study was performed to establish the dynamic behavior in situ of the descending aorta in the human fetus. The pulsatile movements of the vessel walls were recorded in 36 clinically normal fetuses using a real-time phase-locked ultrasonic system measuring echo movements with high spatial and temporal resolution. The mean amplitude of the diameter pulsations was similar in the 28th - 35th week to that in the 36th - 40th week but, as the apparent diastolic diameter increased, the pulse-elicited increment of the cross-sectional area was 29% larger in the older group. The diastolic diameter decreased (p less than 0.001) and the amplitude of the diameter pulsation increased (p less than 0.001) with prolongation of the previous beat interval. The diameter pulse velocity was positively correlated to gestational age (p less than 0.001), ranging between 1.35 and 2.89 m/sec. The incremental phase of the pulse curve diminished in duration with increasing distance from the heart (p less than 0.001) and with decreasing duration of the previous beat interval (p less than 0.001). The maximum slope of the incremental phase was higher in the more distal part of the aorta (p less than 0.001). The study demonstrates that the diameter pulses contain useful information on the cardiovascular dynamics and provides evidence that the Frank-Starling mechanism is effective also in the human fetus.

Aorta, Abdominal↗
PubMed1984

Acute responses to maternal smoking of the pulsatile movements in fetal aorta.

In order to further characterize the acute cardiovascular responses of the human fetus to maternal smoking, 17 women in late pregnancy were studied after smoking a single cigarette. The pulsations of the fetal descending aorta were recorded by means of an ultrasound scanner connected to a phase-locked echo-tracking instrument; the fetal ECG was recorded from abdominal electrodes. Both the level and the wave-form of the diameter pulse curve changed typically 3-25 min after the onset of smoking, concomitant with an increase in maternal and fetal heart rate. Apparent diastolic diameter and pulse amplitude increased, while the ascending part of the curve increased in slope and decreased in duration; the late decremental velocity was reduced. The propagation time from the onset of the fetal Q-wave to the arrival of the pulse wave at the site of recording was reduced. This study demonstrates for the first time the acute effects of maternal smoking on the pulsatile dynamics of fetal vessel walls, and the method suggests the possibility of estimating changes in the contractility of the fetal heart and the afterload in the fetal circulation.

Adult↗
PubMed1984

Acute effects of maternal smoking on fetal heart beat intervals.

The purpose of this study was to analyse the acute effects of maternal cigarette smoking on the fetal heart beat intervals and their variability during the last trimester of a normal gestation. The fetal heart beat intervals were monitored continuously by abdominal electrocardiography for 60 min before and 60 min after smoking in 10 pregnant women. The mean intervals, their long-term variability (SD) and short-term variability (standard deviation of interval differences (SDID], calculated for 30-sec periods, showed a steady state before smoking. During the control period, the mean beat interval was negatively correlated with daily cigarette consumption and the short-term variability was positively correlated with the maternal plasma nicotine level. After smoking, the mean beat interval and the short-term variability decreased transiently, the values of both these parameters being positively correlated with the maternal nicotine values before smoking. The acute response of fetal heart beat intervals and their variability to one cigarette is distinct but transient, and the results suggest that the effects are modified by the chronic smoking habits of the women.

Adult↗
PubMed1983

Screening for fetal malformations using ultrasound and measurements of alpha-fetoprotein in maternal serum.

Fetal ultrasound combined with semiquantitative measurements of alpha-fetoprotein in maternal serum was used for early detection of neural tube defects and omphalocele in 10 147 pregnancies. The accurate assessment of gestational age, obtained by ultrasound, facilitated evaluation of alpha-fetoprotein concentrations in selecting cases for amniocentesis. The advantage of screening with two independent methods is suggested by the finding that eight out of 10 cases with malformations (spina bifida, encephalocele, anencephalus, omphalocele) were detected when both methods were used. Screening by routine ultrasound alone detected only four malformations and by measurement of alpha-fetoprotein alone only seven. The results suggest that, in a low risk population, ultrasound should be combined with the measurement of alpha-fetoprotein in screening for neural tube defects. Measurement of alpha-fetoprotein is indispensable in detection of the small neural tube defects, where the fetus would survive with severe sequelae. The semi-quantitative analysis of alpha-fetoprotein that may be used in combination with ultrasound examination is of negligible cost.

Amniotic Fluid↗
PubMed1983

Variation of semen parameters in fertile men.

The spermiograms of 63 fertile men (whose female partners were pregnant at the time of examination) were evaluated. A wide Gaussian distribution of the different semen parameters was found. Both parametric and nonparametric statistical tests were applied and gave almost identical results. In a subgroup of 34 men, a second semen sample was analysed, but a significant difference (p less than or equal to 0.05) between the two samples was found only regarding the proportion of abnormal forms. Between various semen parameters significant correlations were found. There was no association between follicle stimulating hormone (FSH) and sperm density with sperm counts greater than 20 mill/ml.

Adult↗
PubMed1983

Phase characteristics of breathing movements in healthy newborns.

In the neonatal period, respiratory distortion of the chest wall in active sleep has been reported to reduce the thoracic gas volume. In order to investigate whether the distortion influences the tidal volume, a thorough quantification of the phase differences between the movements of the chest wall and the abdominal wall and the relation of the phase differences to the ventilation was performed on fifteen newborn infants sleeping in prone position. The changes in the circumference of the chest and abdomen were measured with mercury-in-silastic strain gauges; nasal air flow was monitored with a pneumotachograph. During quiet sleep, the movements of the chest wall and the abdominal wall were congruent and regular, and the tidal volume was not dependent on the observed phase differences between them. In active sleep, the breathing movements were incongruent, the tidal volume was negatively correlated with the phase shift between the movements of the chest wall and the abdominal wall, and the mean inspiratory flow was increased. Ventilation (ml/min) did not differ between the sleep states. This study thus suggests that, in healthy newborns in active sleep, the chest wall distortion leads to a reduction of the tidal volume, but ventilation is upheld by compensatory mechanisms, i.e. increased breathing rate and increased amplitude of movements of the diaphragm.

Abdominal Muscles↗
PubMed1983

Acute effects of maternal smoking on fetal breathing and movements.

The acute effects of cigarette smoking on fetal breathing movements and fetal movements were determined with a real-time ultrasound system in 10 healthy habitually smoking women in late gestation. The study was carried out for 1 hour before and 1 hour after the woman smoked a single cigarette. The maternal blood glucose concentration was maintained at a raised postprandial level through the study. After smoking, a significant increase in the rate of fetal breathing movements (P less than .05) appeared together with a reduction in the short time variability of the breath-to-breath intervals (P less than .05). The number of epochs without fetal breathing movements or fetal trunk and limb movements increased after smoking (P less than .05), indicating a change in the spacing of these fetal activities. The increased breathing rate and number of apneic epochs were both correlated to maternal nicotine levels. These observations suggest an acute influence on the fetal behavioral state of maternal smoking.

Blood Glucose↗
PubMed1982

Radioreceptor-assayable somatomedins during pregnancy and their relationship to fetal growth.

Seven women were studied longitudinally throughout clinically normal pregnancy. At three-week intervals, maternal plasma was collected and fetal growth was assessed by ultrasound measurements. Maternal plasma somatomedin concentration was determined by radioreceptor assay, using human fetal brain plasma membrane as matrix and insulin-like growth factor 1 as ligand. In adults this assay primarily detects insulin-like growth factors 1 and 2. Plasma radioreceptor-assayable somatomedin values increased progressively throughout pregnancy. Maternal plasma somatomedin values related to fetal biparietal diameter and showed a significant correlation to birth weight and length.

Adult↗
PubMed1980

Changes in the fetal heart rate associated with fetal breathing and fetal movement.

Thirty-eight recordings of fetal heart rate and fetal activity were made from 21 normal patients between 36 and 41 weeks gestation. Each recording lasted for an average of 39 minutes. The heart rate was measured from beat to beat using the R-wave of the fetal electrocardiogram as the indicator of each heart-beat. Fetal breathing movements and fetal body movements were detected using either A-mode or B-mode ultrasound systems. The relation of fetal breathing and fetal movement to the fetal heart rate was studied both by cardiotachography and computer analysis of the R--R intervals. Fetal body movements (kicking and rolling) were usually associated with a brief tachycardia, the latter typically occurring every two to three minutes. In 14 recordings, the periods of fetal activity were interrupted by periods of fetal rest with an average duration of 12.5 minutes. Fetal breathing was seen in 26 of the 34 recordings analysed and occurred principally during the periods of fetal activity. Fetal breathing was associated with a significant increase in heart rate variation measured as the standard deviation of the R--R intervals and the mean absolute R--R interval difference. Sometimes a pattern of respiratory sinus arrhythmia was seen.

Electrocardiography↗
PubMed1980

Zygosity and intrauterine growth of twins.

Six hundred seventy-eight sonar measurements of the fetal biparietal diameter (BPD) were used to assess the intrauterine growth of 182 twins between 18 and 40 weeks' gestation. These values, as well as the weight and body length at birth, were related to the zygosity, which was determined by sex of the infants, histologic examination of placenta, or blood grouping. The mean BPD of twin 1 was larger than that of twin 2 in both monozygotic and dizygotic pairs throughout the study period (P less than .001). The size of BPD of the dizygotic infants exceeded that of the monozygotic among both twin 1 (P less than .001) and twin 2 (P less than .001). The absolute intrapair differences of birth length and weight were larger among dizygotic than among monozygotic twins. These findings suggest that in late pregnancy a substantial one-way intertwin transfusion among monochorial twins does not occur frequently enough to mask the inherent genetically determined similarity between the twins. The appearance already in the second trimester of the difference in the longitudinally monitored BPD between monozygotic and dizygotic twins suggests that the discrepancy is determined early in gestation.

Adolescent↗
PubMed1979

Fetal breathing movements and maternal exercise.

Earlier statements that fetal breathing movements (FBM) are sensitive to changes in the fetal homeostasis prompted the study of the effect of maternal exercise on FBM and fetal heart rate. Forty women in the last trimester of gestation were subjected to a work load (80 W) for 5 min on a bed ergometer cycle; in 30 of them FBM were recorded by A-mode ultrasound, and in 10, the fetal heart rate was monitored by continuous ultrasound. Maternal blood pressure, pulse rate, blood pH and pCO2, and transcutaneous pO2 were also followed. The FBM showed a transient marked increase in incidence immediately after the end of the exercise. No changes in basal level or in baseline variability of the fetal heart rate were found in the recovery period after work. Some possible causes of the observed FBM alterations are discussed. The findings imply that, after this particular form of stress, FBM are a more sensitive indicator of the physiological state of the fetus than the fetal heart rate.

Adult↗
PubMed1979

Effects on fetal breathing movements of maternal challenges. Cross-over study on dynamic work, static work, passive movements, hyperventilation and hyperoxygenation.

Ten women in the last trimester of a normal pregnancy were subjected to five different loads in a cross-over study. Fetal breathing movements (FBM), fetal heart rate (FHR), maternal heart rate (MHR), and mean arterial pressure (MAP), maternal transcutaneously measured pO2 (Tc-pO2), and the energy supply to the Tc-pO2 electrode were recorded continuously before, during, and after the load. Maternal capillary pH and pCO2 were measured at three representative time points. The immediate responses of the incidence of FBM to the different challenges were: increase after dynamic work (bicycle test); no change after static work (isometric muscle contraction) and passive movements; decrease after hyperventilation and hyperoxygenation. FHR was unaffected by all challenges. The FBM incidence varied in parallel with pCO2 after dynamic work and hyperventilation and inversely with the Tc-pO2 rise caused by hyperoxygenation. Maternal pH was increased after passive movements (no change in FBM) and after hyperventilation (decreased incidence of FBM), FBM seem to be more sensitive to environmental changes than is the FHR. Mechanical stimuli to the uterus were not responsible for the augmentation of FMB seen after the bicycle test. The present observations reveal the multifactorial nature of the regulation of FBM, and support the role of CO2 as a major stimulator of breathing movements also in prenatal life.

Adult↗
PubMed1979

On improved outcome of twin pregnancies.

During the past four years, an attempt has been made in Malmö to reduce the frequency of preterm termination of twin pregnancies. For this purpose, the entire pregnant population of this medium-sized city was subjected to general ultrasonic screening in the second trimester. This detected 88 per cent of the twin pregnancies. The screening has a methodological error of 2 per cent. Eightysix of the women with twin pregnancy were subjected to bedrest in hospital for more than two weeks in the second half of gestation. The incidences of twins born with birth weight below 1 500 g and of twins light-for-gestational-age were reduced compared with those a decade earlier. Also the group of twins born before the 37th week decreased, and the perinatal mortality rate fell to the same level as in singleton pregnancies. Early detection of twin pregnancies followed by rest for the pregnant women seems to contribute to an improved outcome of these gestations.

Birth Weight↗