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Biomedical subjects

H N Macdonald

Publications and source records attributed to H N Macdonald.

At least 19 recordsLinked to original sources
PubMed1990

Inconsistencies in clinical decisions in obstetrics.

Analysis of the increasing incidence of caesarean section in an English teaching hospital over a 15-year period revealed that emergency caesarean section for the diagnosis of fetal distress in labour made a major contribution to this increasing trend. A retrospective audit of a sample of these operations by the consultants of the hospital indicated that 30% of the operations were unnecessary. There were two other disturbing findings in our audit. First, there was significant disagreement between auditors in the decision whether to do a caesarean section or not. Second, and perhaps more importantly, when faced with identical information at a different time, the auditors were inconsistent in 25% of cases. The disturbing clinical situation highlighted by this study may have implications for medical jurisprudence.

Cesarean Section↗
PubMed1990

Randomized comparison of routine vs highly selective use of Doppler ultrasound and biophysical scoring to investigate high risk pregnancies.

OBJECTIVE: To compare routine versus highly selective use of Doppler ultrasound and biophysical scoring in higher risk pregnancy. DESIGN: A pragmatic randomized trial. SETTING: St James's University Hospital, Leeds. SUBJECTS: 500 pregnant women at high risk of intrauterine growth retardation or still birth. INTERVENTIONS: Regular monitoring with biophysical profile assessment and Doppler velocity waveform recording in umbilical and uteroplacental arteries. Results immediately available to clinicians. MAIN OUTCOME MEASURES: Gestational age at delivery, obstetric intervention rates and short-term neonatal morbidity. RESULTS: Risk factors were distributed very evenly between the 250 patients in the study and control groups respectively. A total of 902 biophysical profile and Doppler assessments were done in the 250 study group patients and only in 12 patients in the control group. In the study group, absent end-diastolic flow was found in only 2.7% of all 902 measurements. A persistently abnormal biophysical score was always associated with absence of end-diastolic flow. The mean gestational age at induction of labour was statistically and clinically similar in the two groups and there was no overall statistically significant difference in intervention rates between the two groups. There was a statistically significant lower frequency of depressed 5-min Apgar scores in the study group. Serious neonatal morbidity was also statistically significantly more common in the control group than in the study group. CONCLUSIONS: The use of Doppler ultrasound in higher risk pregnancies does not lead to an increase in iatrogenic preterm delivery. The total rate of positive tests on Doppler ultrasound is very low and persistently abnormal biophysical scores are unlikely to be found in patients where umbilical end-diastolic blood flow is present. Surrogate measures for fetal damage seem to be improved when clinicians have access to Doppler ultrasound assessments.

Adult↗
PubMed1983

Nutrient intake and associated biochemical status of pregnant Asians in the United Kingdom.

Forty-six women (17 Pakistanis, 19 Indians, ten Bangladeshis) at 8 to 20 weeks of pregnancy were studied during November to January. Dietary intake was assessed by the diet history method. Mean energy intakes (+/- s.d.) for the Pakistanis, Indians and Bangladeshis were 9.80 (1.99), 8.08 (1.59) and 6.95 (1.70) MJ. Intakes of protein, calcium, phosphorus and iron were positively correlated with energy intake. Vitamin D intake was similar in all groups, mean (+/- s.d) = 2.15 (1.39). Mean serum (+/- s.d.) protein, phosphorus and calcium were 70.9 (6.5) g/l; 2.27 (0.12) mmol/l; 1.00 (0.21) mmol/l and fell within the lower normal range. Mean haemoglobin was 12.2 (1.1) g/dl. Mean (+/- s.d.) serum 25-OHD for Pakistanis, Indians and Bangladeshi respectively was 3.80 (2.25), 4.04 (2.64) and 5.22 (2.47) ng/ml. These are within the range found for patients with osteomalacia (less than 10 ng/ml) and substantially lower than values of 14.6 (2.6) ng/l reported by Bashir et al. (1981) for September and October.

Asia, Western↗
PubMed1981

Biochemical evidence of vitamin D deficiency in pregnant Asian women.

Levels of plasma 25-hydroxy-vitamin D (25 OHD) were found to be lower in 58 pregnant Asians when compared with 59 Caucasian controls. Thirty per cent of Asians and none of the controls had levels less that 10 ng/ml. The low plasma was associated with biochemical evidence of secondary hyperparathyroidism and increased bone turnover as assessed by plasma parathyroid hormone, alkaline phosphatase and urinary hydroxyproline. Vitamin A and its binding protein, and vitamin D binding protein, were also measured in a subgroup of 40 patients. There was no difference between Asians and their controls. The data suggest that vitamin D supplementation would be beneficial in Asian women during pregnancy.

Asia↗
PubMed1980

Altered haemorheology in oral-contraceptive users.

The haemorheological profile of the menstrual cycle was determined in 12 women who did not take oral contraceptives and compared with that in two groups of women (n = 8 and n = 30) who had been taking oral contraceptives for at last six months. Packed cell volume, platelet count, erythrocyte deformability, plasma fibrinogen concentration, and plasma and whole-blood viscosity varied cyclically throughout the menstrual cycle in the 12 non-users. This variation was abolished by the use of oral contraceptives, and the values of these indices were raised by an amount likely to predispose to thrombosis.

Adult↗
PubMed1979

Influence of preinduction prostaglandin E2 vaginal gel on cervical ripening and labor.

A sterile gel containing prostaglandin (PG) E2 (2 mg PGE2 10 ml gel) was instilled vaginally in 65 primigravidas with unripe cervixes to accelerate ripening before planned surgical induction of labor. The patients treated with the gel were compared with 30 similar untreated controls. In the PGE2-treated group a significant improvement on cervical score was achieved before labor began, and 47% began to labor "spontaneously" without further treatment. Both the duration of subsequent labor and the incidence of cesarean section were significantly lower in the PGE2-treated group. There were no unwanted fetal or maternal effects. Pretreatment with intravaginal PGE2 gel reduces the risk of failed induction and provides the mother with an experience similar to spontaneous labor without harming the fetus.

Adult↗
PubMed1978

Interpretation of urinary oestrogen:creatinine ratio for monitoring fetoplacental function in late pregnancy.

In pregnancies with a normal outcome the oestrogen:creatinine ratio in early morning samples of urine showed a smaller day-to-day variation than the ratio in 24-h urine or the 24-h total oestrogen excretion, and a significant fall could be detected more easily. Patients admitted to hospital who eventually delivered a healthy baby provided a reference range which, after logarithmic transformation, increased linearly with period of gestation. A fall in log10 oestrogen:creatinine ratio exceeding 40% of this range is unusual in pregnancies with a healthy outcome, and suggest impaired fetoplacental function.

Creatinine↗
PubMed1976

The failure of pyridoxine in suppression of puerperal lactation.

The benefits of pyridoxine in the suppression of lactation were assessed in a double blind controlled trial on 175 puerperal women. No significant differences were demonstrated between pyridoxine and the placebo whether assessed by subjective discomfort or by the persistence of lactation.

Clinical Trials as Topic↗
PubMed1976

Plasma solute concentrations during gonadotrophin-induced ovulation.

The effects of ovulation induction on some plasma solute concentrations were investigated serially in eleven women, nine of whom conceived in that cycle. Increasing oestrogen output during the follicular phase was associated with decreasing levels of osmolality, urea, total protein and the albumin free protein fraction. Smaller decreases in the concentrations of sodium, potassium, chloride, carbon dioxide combining power (CO2CP) and albumin were not statistically significant. The luteal phase was marked by a rise in osmolality and a fall in CO2CP but no other significant changes. Levels of osmolality, sodium and potassium fell in early pregnancy when oestrogen output was further increased. These results appear consistent with an oestrogen induced expansion of the extracellular fluid compartment by retention of water in excess of solute, which might also account for the similar changes in pregnancy.

Blood Proteins↗
PubMed1976

Haematological changes during ovulation-induction by gonadotrophins.

The oestrogen response to ovulation-induction by gonadotrophins initiates a preovulation rise in total leucocytes and promotes fluid retention. In consequence of the latter, cyclic changes occur in blood haemoglobin and the haematocrit. The level of oestrone excretion in the follicular phase of induced cycles indicates that multiple follicular development probably occurs, and this also appears to affect the luteal phase. It seems likely, therefore, that the data present a rather exaggerated picture of the situation which obtains in normal menstrual cycles.

Blood↗