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Biomedical subjects

B N Walters

Publications and source records attributed to B N Walters.

12 recordsLinked to original sources
PubMed1992

The epidemiological characteristics of unexplained antepartum stillbirths.

All antepartum stillbirths weighing 1000 g or more born in Western Australia from 1980 to 1983 were categorised as 'unexplained' or 'explained' based on information from Perinatal Death Certificates. Using data from hospital and doctors' antenatal records a number of variables in each stillbirth category were compared by unconditional logistic regression. Significant differences were observed between the two groups in medical disorders and abnormalities of pregnancy, thus confirming our classification system. Compared with mothers of 'explained' antepartum stillbirths, mothers of unexplained antepartum stillbirths tended to have younger ages at delivery and had associated lower parity, more antenatal visits to the medical practitioner, fewer hospital admissions, a greater chance of having received care by a general practitioner than by a specialist obstetrician and were of more advanced gestation at the time of diagnosis. The results of this study indicate that the epidemiological characteristics of pregnancies resulting in unexplained antepartum stillbirths differ from those resulting in explained antepartum stillbirths. This suggests that unexplained antepartum stillbirths are not merely the result of inadequate obstetrical management but consist of a series of fetal disease states which are not currently amenable to detection.

Case-Control Studies↗
PubMed1992

A case-control study of unexplained antepartum stillbirths.

OBJECTIVE: To ascertain factors that will identify women who are at increased risk of unexplained antepartum stillbirth. DESIGN: Matched case-control study. The cases and controls were initially analysed as a whole group and again after dichotomizing into those of low birthweight (< 2500 g) and those of normal birthweight (> or = 2500 g). SETTING: Western Australia 1980-1983. SUBJECTS: Unexplained antepartum stillbirths of > or = 1000 g birthweight (cases) and liveborn infants individually matched for year of birth, plurality, sex and birthweight of infant and race of mother (controls). RESULTS: The case pregnancies had more polyhydramnios (OR 10.83, 95% CI 2.41-48.69) and cord problems (OR 6.57 95% CI 1.36-31.75) than the controls but, paradoxically, other obstetric and medical complications were less common in the cases. The association with polyhydramnios persisted when the analysis was confined to those with low birthweight. With normal birthweight fetal distress was more frequent in the cases (OR 3.65 95% CI 1.36-9.80) but there were few other differences. CONCLUSIONS: The clinical and diagnostic systems currently in use are unable to identify many fetuses at risk of death. Decreases in the rate of unexplained antepartum stillbirths await the discovery of new preventable causes, or of innovations in clinical or laboratory aspects of obstetric care.

Birth Weight↗
PubMed1989

Pre-eclampsia.

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Female↗
PubMed1988

Acute fatty liver of pregnancy: clinical features and diagnosis.

Five cases of acute fatty liver of pregnancy are described. These are the only recognized cases of this disorder occurring in a 2 year period in Western Australia. Clinical and laboratory features are presented. There was no maternal death. Of the six babies, there were three intrauterine deaths, including the only set of twins. All the babies were male. Vomiting in the third trimester was the chief presenting feature in all cases, often accompanied by a systemic illness with malaise and tiredness. Extreme polydipsia was noted as a prominent symptom in all cases. The combination of moderately abnormal liver function tests, extreme leucocytosis with other blood film abnormalities, hypoglycaemia, impaired renal function, coagulopathy and gross elevation of uric acid level is regarded as highly suggestive of the diagnosis. Features of a preeclamptic illness were present in several cases. Three of the patients have since had uneventful pregnancies. The constellation of clinical and laboratory features is sufficiently characteristic to allow accurate clinical diagnosis in most cases of this disorder. The chances of both maternal and fetal survival are enhanced by early diagnosis allowing intervention in the form of prompt delivery of the infant.

Acute Disease↗
PubMed1987

Placental glycolysis and energy metabolism in preeclampsia.

We examined the possibility that in preeclampsia complicated by fetal growth retardation, placental energy state is low either because of impaired glycolysis or because of ischemia resulting from reduced maternal placental blood flow. Concentrations of pyruvate and lactate, but not of glycogen and glucose, were significantly low in placentas of mothers with severe preeclampsia, supporting previous indirect evidence of inhibited glycolysis. Nevertheless, direct measurements of adenine nucleotide concentrations did not indicate reduced placental energy level in the preeclamptic placentas. This along with a lack of change of the ratio of lactate/pyruvate concentration (an indication of the redox state of cytoplasmic reduced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide) is also evidence against the hypothesis of general placental ischemia leading to energy deficiency. However, as glycolysis is an important source of precursors, particularly pyruvate, for synthesis of amino acids and lipids, these results suggest that there is a significant metabolic abnormality in placentas of mothers with severe preeclampsia.

Adenine Nucleotides↗
PubMed1986

Blood pressure in the puerperium.

Blood pressure was measured by random zero sphygmomanometer in the morning and afternoon for 5 days after normal delivery in a group of 136 previously normotensive women. The number of women studied each day varied from 32 to 125. The afternoon blood pressure was higher than the morning blood pressure (differences: 1.7 mmHg systolic, 2.6 mmHg diastolic; P less than 0.05). Both systolic and diastolic blood pressures rose for the first 4 days after delivery. The average rise over the whole period was about 6 mmHg systolic and 4 mmHg diastolic (P less than 0.05). A considerable number of previously normotensive women displayed elevations of blood pressure in the puerperium. Twelve per cent of all patients exceeded a diastolic blood pressure of 100 mmHg.

Adolescent↗
PubMed1985

Prophylaxis of thromboembolism in pregnancy: an alternative.

Twenty-six pregnancies in women who had one or more episodes of thromboembolism in the past were managed by a regimen in which routine antenatal prophylactic anticoagulation was not given, apart from during delivery which was covered with intravenous infusion of dextran 70. After delivery, these patients received either subcutaneous heparin for 6 weeks or subcutaneous heparin for 1 week, followed by 5 weeks of warfarin. One patient (4%) possibly developed an episode of thromboembolism in the antenatal period. There were no episodes of postnatal thromboembolism. There were two spontaneous mid-trimester abortions and no perinatal losses. There were no significant complications or reactions related to the use of dextran, heparin or warfarin.

Adult↗
PubMed1985

alpha-Fetoprotein elevation and proteinuric pre-eclampsia.

In a retrospective study of pregnancy complicated by unexplained elevation of maternal serum alpha-fetoprotein (AFP), 60 patients were compared with 120 control subjects. Proteinuric pre-eclampsia occurred in 13% of the study patients compared with 1% of the control subjects. Primiparity, previous mid-trimester abortion and recurrent abortions were also significantly more common in the study group. It is proposed that an abnormality of the placenta predisposes to complications and that this abnormality is expressed early in pregnancy when the AFP level is first measured. This group of women is at high risk of adverse pregnancy outcome and requires careful monitoring.

Abortion, Spontaneous↗