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Biomedical subjects

B J Trudinger

Publications and source records attributed to B J Trudinger.

At least 19 recordsLinked to original sources
PubMed2001

Misoprostol versus dinoprostone for cervical priming prior to induction of labour in term pregnancy: a randomised controlled trial.

A prospective randomised controlled trial was performed to compare the efficacy and safety of intravaginal misoprostol to that of intravaginal dinoprostone when used for cervical priming prior to the induction of labour; 126 women were recruited to the study and randomised to receive either intravaginal dinoprostone (n = 63) or misoprostol (n = 63) for cervical priming prior to induction of labour. The mean time from insertion of the priming agent to vaginal delivery was significantly shorter in the misoprostol group (925.8 versus 1577.6 minutes), the mean duration of the active length of labour was significantly shorter in the misoprostol group (353.7 versus 496.8 minutes) and more women in the misoprostol group delivered in less than 12 hours (92% versus 76.5%). Women in the misoprostol group were less likely to require a repeated dose of prostaglandin for cervical priming and less likely to require oxytocin for augmentation of labour. There was no difference in the number of women who were delivered vaginally or by Ceasarean section between the two groups. More women developed hyperstimulation during labour in the misoprostol group; however there was no difference between the groups in neonatal outcome in respect to low cord pH or Apgar score at delivery or admission to the neonatal special care nursery.

Adult↗
PubMed2000

Elevated circulating homocyst(e)ine levels in placental vascular disease and associated pre-eclampsia.

We examined the hypothesis that hyperhomocyst(e)inaemia in the maternal or fetal circulation is associated with placental vascular disease with either the maternal syndrome of pre-eclampsia and/or fetal syndrome of growth restriction. Maternal plasma homocyst(e)ine levels were significantly higher in pregnancies complicated by pre-eclampsia, pregnancies with evidence of umbilical placental vascular disease, and pregnancies with both complications compared with the normal pregnancy group. In the fetal circulation mean plasma homocyst(e)ine concentration was significantly higher in the pre-eclampsia group compared with the normal group. The results suggest that hyperhomocyst(e)inaemia may be a risk marker for placental vascular disease and maternal pre-eclampsia. The elevated fetal plasma homocyst(e)ine concentrations, found only in the group of pregnancies with pre-eclampsia in the absence of umbilical placental vascular disease, may be due to an effect of placental vascular disease on homocyst(e)ine transfer from the maternal to fetal circulation.

Adult↗
PubMed2000

Ultrasound measurement of biparietal diameter and umbilical artery blood flow in the normal fetal guinea pig.

BACKGROUND AND PURPOSE: Measurement of the biparietal diameter (BPD) by use of B-mode ultrasound provides a useful means for assessment of gestational age and brain growth in humans during pregnancy. Recording of flow velocity waveforms from the umbilical artery, using Doppler ultrasound, is used to assess development of the fetal placental circulation. We sought to measure these ultrasound parameters during normal pregnancy in the guinea pig and develop normative data. METHODS: Measurements of BPD were made on 205 fetuses of various gestational ages; 114 fetuses had 2 or more serial studies performed (total n = 474). RESULTS: BPD increased from 0.806cm at 22 to 26 days, to 1.922cm at term (69 days), (y = -0.00043x2 + 0.06881x - 0.75941, with an r value of 0.995, where x = days' gestation, y = biparietal diameter [cm]). Umbilical artery flow velocity waveform resistance index (RI) decreased as gestation advanced (y = -0.012x + 1.294 with an r value of 0.887, where x = days gestation, y = RI) reflecting expansion of the placental vascular bed. CONCLUSIONS: It is possible to use ultrasound to study pregnancy in the guinea pig. The BPD may be used to estimate gestational age. Resistance to blood flow in the placenta may be assessed using the RI derived from the umbilical artery flow velocity waveform.

Animals↗
PubMed1995

HLA-G deletion polymorphism and pre-eclampsia/eclampsia.

OBJECTIVE: To investigate a HLA-G deletion polymorphism in pre-eclamptic pedigrees and the general population. DESIGN: A population association study of HLA-G genotypes from pre-eclamptic/eclamptic patients and control groups. SETTING: Analyses undertaken in the School of Biological Sciences, Macquarie University. Patients were from Royal Women's Hospital, Melbourne, and controls were from Westmead Hospital and Macquarie University, Sydney. SUBJECTS: One hundred and ninety-six individuals, consisting of 29 pre-eclamptic/eclamptic (PE/E) patients, 13 individuals born of a PE/E pregnancy, 46 blood relatives of PE/E patients, 21 husbands of PE/E patients, 25 women normotensive in first pregnancy, 15 husbands of women normotensive in first pregnancy and 47 staff and students of Macquarie University. RESULTS: Genotypic and gene frequencies were not significantly different in the seven groups examined. CONCLUSION: There is no detectable relationship between susceptibility to pre-eclampsia or being born of a pre-eclamptic pregnancy and HLA-G genotype.

Eclampsia↗
PubMed1994

Aortic Doppler velocity measurement and cardiac function in the fetal lamb.

Aortic haemodynamic parameters, and Doppler waveforms in particular, were investigated in acute experiments with fetal lambs. Cardiovascular changes were produced by central infusion of the drugs esmolol and dopamine. Pulsed Doppler waveforms were obtained from the descending thoracic aorta, simultaneous with recordings of pulsatile aortic volume flow rate, diameter and blood pressure. The relation between Doppler-derived velocities and the corresponding full vessel lumen velocities was shown to be fairly linear and consistent across different animals. The aortic volume flow per beat decreased with esmolol (p < 0.003, repeated measures ANOVA); the Doppler and vessel lumen mean velocities also decreased, whether measured only at peak systole or over the full cardiac cycle (at most p < 0.003). With dopamine the aortic flow per beat increased (p < 0.001), as did the Doppler and vessel lumen mean velocities (at most p < 0.02). An inverse relation between the aortic flow per beat and the peripheral resistance was observed. To identify inotropic changes in the presence of vascular effects, a theoretical model based on cardiac power output changes was implemented. The data were divided into three groups, according to whether the model did or did not identify a definite inotropic effect (positive or negative). The Doppler velocity changes for these three groups were different (p < 0.0001). The mean Doppler velocity increased by 7 cm s-1 in the positive inotropic effect group, and decreased by 4 cm s-1 in the negative group. The aortic flow parameters of the human fetus are very similar to those of the fetal lamb.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1993

Erythrocytes in fetuses with abnormal umbilical artery flow velocity waveforms.

OBJECTIVE: Our purpose was to measure erythrocyte indexes in fetuses with two grades of Doppler-defined umbilical placental insufficiency. STUDY DESIGN: A prospective study comprising 110 infants categorized into control, moderate, and severe groups by umbilical artery waveform studies was undertaken at the University of Sydney at Westmead Hospital. Fetal erythrocyte indexes were measured in umbilical venous blood. Multivariate analyses of variance with post hoc Bonferroni t tests were used in the statistical analysis. RESULTS: The erythrocyte count, hematocrit, and hemoglobin concentration were all significantly higher (p < 0.001) in the two placental insufficiency groups than in the controls. Both placental insufficiency groups were affected to the same extent. CONCLUSIONS: Differences exist in the erythrocyte populations of fetuses with Doppler-defined placental insufficiency compared with controls. Importantly, these differences occur in more than just the most severe cases. These changes may represent a compensatory response to the placental vascular lesion detected by abnormal umbilical artery waveforms.

Blood Flow Velocity↗
PubMed1993

Angiotensin sensitivity predicts aspirin benefit in placental insufficiency.

OBJECTIVE: To determine whether the beneficial effects of aspirin in the treatment of Doppler umbilical placental insufficiency correlate with the maternal pressor response to angiotensin infusion. DESIGN: An open trial. SETTING: A tertiary referral obstetric service. PATIENTS: Women identified at between 25 and 36 weeks of pregnancy with an elevated umbilical artery Doppler systolic/diastolic (S/D) ratio and a positive pressor response to angiotensin infusion. INTERVENTION: Low dose aspirin (100mg/day) treatment of mothers. MAIN OUTCOME MEASURE: Fetal and placental size at delivery in relation to subsequent maternal angiotensin responsiveness. RESULTS: Women who converted from a positive angiotensin pressor response to angiotensin refractoriness after aspirin administration had larger infants and placentas compared with those whose response remained positive. CONCLUSION: Angiotensin sensitivity predicts women with umbilical Doppler detected placental insufficiency responding to aspirin therapy. Loss of the normal refractory response in pregnancy may be a consequence of vascular pathology in the placenta.

Angiotensins↗
PubMed1993

The coagulation system in placental insufficiency: a study in the fetal circulation.

OBJECTIVE: To examine the hypothesis that Doppler-defined umbilical placental insufficiency is associated with intravascular coagulation in the fetal circulation. DESIGN: A prospective, descriptive, single centre study. SETTING: The University of Sydney, Department of Obstetrics at Westmead Hospital. SUBJECTS: Ninety-one infants were classified on the basis of the systolic:diastolic (SD) ratio of the umbilical artery flow velocity waveforms into severe (SD > 99.9th centile), moderate (SD > 95th centile) or control groups. INTERVENTION: Blood was collected from the umbilical vein at delivery. MAIN OUTCOME MEASURES: The coagulation variables measured were the plasma concentrations of thrombin-antithrombin, fibrinopeptide A and fibrinogen, the antithrombin III activity, the prothrombin time and the activated partial thromboplastin time. RESULTS: There were no differences in activated partial thromboplastin time, antithrombin III activity, fibrinopeptide A or thrombin-antithrombin complex concentrations between fetuses with placental insufficiency and those with no placental disease. Fetuses with severe and moderate placental insufficiency had a statistically significant prolongation of their mean prothrombin time compared to controls (23.7 +/- 0.8, 23.6 +/- 1.6, and 19.9 +/- 0.6 s, respectively). Infants in the severe group had a lower plasma fibrinogen concentration than control fetuses (1.66 +/- 0.09 and 1.94 +/- 0.09 g/l, respectively). The activated partial thromboplastin time and antithrombin III activity were both highly dependent on gestational age. CONCLUSIONS: These results do not support the hypothesis that Doppler-defined umbilical placental insufficiency is associated with activation of coagulation in the fetal circulation.

Antithrombin III↗
PubMed1992

Antenatal tests of fetal welfare and development at age 2 years.

OBJECTIVE: Our objective was to examine the outcomes at 2 years of age of fetuses delivered electively before 34 weeks, studied antenatally with two tests of fetal well-being. STUDY DESIGN: Forty-two fetuses from high-risk pregnancies delivered electively by cesarean section before 34 weeks were stratified into normal versus abnormal subgroups with umbilical Doppler flow velocity waveform and fetal heart rate results. Developmental outcome was assessed at 2 years. Two comparison groups were also selected: 40 matched premature controls delivered spontaneously before 34 weeks and 67 normal babies delivered spontaneously at term. Frequency outcome data were tested with chi 2 analyses and the remainder with analyses of variance. RESULTS: Within the electively delivered study group poor cognitive progress at 2 years was more strongly associated with an abnormal fetal heart rate result than an abnormal Doppler result. Compared with the premature control and normal term groups, electively delivered fetuses were significantly delayed in growth, cognition, and motor development (p < 0.005). CONCLUSIONS: Adverse fetal welfare in a high-risk obstetric sample was associated with poorer outcome at 2 years. However, the whole of the group of fetuses from such high-risk pregnancies showed significant developmental delay compared with normal term children and, more importantly, matched premature infants delivered spontaneously from otherwise uncomplicated pregnancies.

Cesarean Section↗
PubMed1992

Sonographic evaluation of intrauterine growth retardation.

The prenatal recognition of the growth-retarded fetus is important because of the associated increased perinatal morbidity. Clinical methods of assessing fetal growth are disappointing and necessitate that a high-risk group be identified for more intensive surveillance. This review discusses the role of ultrasound biometry in establishing whether a fetus is small. Behavioral characteristics of the fetus may also be assessed using real-time ultrasound. The realization that not all small fetuses are a result of growth failure has led to the development of Doppler ultrasound to identify the fetus at risk. This paper focuses on the evidence supporting the selected use of Doppler ultrasound to investigate high-risk pregnancy.

Female↗
PubMed1991

Fetal umbilical artery velocity waveforms and subsequent neonatal outcome.

Flow velocity waveforms (FVWs) from the fetal umbilical artery were recorded from 2178 pregnant women over a 6-year period. All of them had an obstetric factor indicating increased risk of fetal compromise. A total of 6749 studies was recorded. The systolic diastolic (AB) ratio was measured and classified as normal (less than 95th centile), elevated (95-99th centile), high (greater than 99th centile) or extreme (absent diastolic flow). The results of these studies have been related to subsequent fetal and neonatal outcome. An abnormal umbilical artery FVW was associated with shorter gestation and infants with lower birthweight, shorter length and lower ponderal index. There was a highly significant association between an abnormal FVW and the birth of an infant small for gestational age. The significance of the association increased with the increased abnormality of the umbilical artery FVW and this was independent of gestational age. Preterm infants associated with high or extreme AB ratios spent twice as long in the neonatal nursery than those with normal AB ratios. Analysis of 794 pregnancies studies serially indicated that an abnormal FVW in which the AB ratio was increasing, in contrast to a decreasing AB ratio, predicted a poor outcome for both size at birth and duration of neonatal intensive care. We conclude that in high risk pregnancy Doppler umbilical artery FVW studies predict the most compromised fetuses in terms of growth retardation and requirements for neonatal intensive care.

Adult↗
PubMed1991

Maternal angiotensin sensitivity and fetal Doppler umbilical artery flow waveforms.

The angiotensin pressor response was investigated in normotensive pregnancies which had umbilical Doppler flow velocity waveforms suggestive of placental vascular disease. Of the 36 pregnancies studied at between 24 and 38 weeks gestation, 18 had a positive response to the angiotensin pressor test, these women were delivered earlier (35.3 vs 38.5 weeks, P = 0.015), had a lower mean birthweight centile (14 vs 36, P less than 0.001) and higher frequency of fetal distress in labour (40% vs 7%, P = 0.06) when compared with the 18 women who had a negative response. The Doppler umbilical systolic-diastolic (S-D) ratio decreased with gestation in the negative group, suggesting continuing placental growth and vascular expansion, whereas the S-D ratio increased in the positive group (P less than 0.001), indicative of vascular obliteration. We suggest that the positive angiotensin pressor response is primarily associated with the placental vascular pathology. Angiotensin infusion had no acute effect on maternal uteroplacental or fetal umbilical artery flow velocity waveforms.

Angiotensin II↗
PubMed1991

Fetal platelet consumption: a feature of placental insufficiency.

The involvement of fetal platelets in placental insufficiency was investigated. Platelet life span and the rate of platelet turnover were measured by a novel technique in fetuses with moderate and severe placental insufficiency and in controls. This procedure involves the measurement of platelet count and concentration of free glycocalicin in plasma. Placental insufficiency was defined by antenatal Doppler ultrasound analysis of the umbilical artery waveform, which was used to categorize the subjects according to whether their systolic-diastolic ratios were normal, moderately raised, or severely raised. Mean platelet life span in fetuses affected by placental insufficiency was only 60% of the normal fetal platelet life span (P less than .001). In addition, affected fetuses had a higher rate of platelet turnover, reflected in an elevated plasma glycocalicin concentration (4.06 +/- 0.19 versus 3.28 +/- 0.15 microgram/mL for severe placental insufficiency and control fetuses, respectively; P less than .01). Platelet life span did not differ between the moderate and severe placental insufficiency groups. We hypothesize that the observed changes in platelet life span and turnover result from increased platelet activation, which plays a role in the development of placental insufficiency.

Female↗
PubMed1990

Doppler waveform pulsatility index and resistance, pressure and flow in the umbilical placental circulation: an investigation using a mathematical model.

A mathematical model of the umbilical placental circulation was used to examine the effect of different physiological variables on the pulsatility index (PI) of the umbilical artery Doppler waveform. The variables include the umbilical and placental resistances, the volume flow rate and the pressure. In the model the branching structure of the placental villous tree is considered in detail, while each arterial branch is itself represented simply using a resistor and a capacitor. Placental vascular disease is modelled as obliteration of a fraction of the terminal branches of the tree. The model umbilical artery PI depends on the ratio of the placental resistance to the umbilical artery resistance. The PI increases with vascular disease, but the rate of increase is not uniform. Initially, the placental resistance and the PI increase very slowly with vessel obliteration. Once the level of vessel obliteration has reached a large enough value--typically between 60% and 90% obliteration--the PI begins to rise sharply. A larger placental vascular bed can accommodate a greater level of vessel obliteration before this rapid PI rise begins. The umbilical artery PI also depends on the pulsatility of the input (aortic bifurcation) pressure waveform, but blood pressure variations in the physically attainable range cannot account for the very high PI values associated with fetal compromise. Physically attainable pressure waveform changes would, however, enable the fetus with substantial placental vascular disease to maintain umbilical volume flow rate, and at the same time exhibit a raised umbilical artery PI value.

Blood Flow Velocity↗
PubMed1990

The fetal breath cycle.

Fetal breathing movements may be timed precisely from the umbilical vein flow velocity profile recorded using Doppler ultrasound. Serial studies were performed on eight normal fetuses from 28 weeks pregnancy until delivery. Measurements were made of the inspiratory time, total breath time and breath amplitude. There was a clear change in the pattern of fetal breathing with advancing gestation. The inspiratory time lengthened and the amplitude of each breath increased. The variability of these measures decreased. The timing equation ti/ttotal lengthened. The area of change in the umbilical vein sonogram was calculated as a measure of respiratory work and this increased with gestation. It is suggested that the changing pattern of fetal breathing movements reflects changes in central control of breathing in the fetus and parallels observations in the newborn.

Embryonic and Fetal Development↗