Search PubMed⌕ Search

Biomedical subjects

I Chalmers

Publications and source records attributed to I Chalmers.

At least 91 records · Page 5Linked to original sources
PubMed1989

Retrospective and prospective identification of unpublished controlled trials: lessons from a survey of obstetricians and pediatricians.

Investigations in which statistically significant differences between treatment groups have not been observed are less likely than others to be reported in scientific journals. In clinical research, this selective suppression of "negative" results may lead to the adoption of ineffective or hazardous treatments. In an attempt to obtain information about unpublished trials in perinatal medicine, letters were sent to 42,000 obstetricians and pediatricians in 18 countries. As a result, we were notified of 395 unpublished randomized trials. Only 18 of the trials had been completed more than 2 years before the survey, a period during which at least 2300 reports of perinatal trials had been published. Of the 395 unpublished trials, 125 had ceased recruitment within the 2 years prior to the survey, 193 were actively recruiting at the time of the survey, and 59 were about to begin recruitment. It was concluded that publication bias will not be addressed successfully by attempts to obtain information about unpublished trials retrospectively. However, since the response rate to our request for details about ongoing and planned trials was good, prospective registration of trials at inception appears to be a feasible approach to reducing publication bias and its adverse consequences. An additional merit of prospective registration of clinical trials is that it should reduce unnecessary duplication (as opposed to necessary replication) in research and promote more effective collaboration.

Clinical Trials as Topic↗
PubMed1988

The effects of routine oxytocic administration in the management of the third stage of labour: an overview of the evidence from controlled trials.

Recent claims that routine active management of the third stage of labour increases rather than decreases maternal and neonatal morbidity have prompted us to conduct a systematic review of the relevant controlled trials. In this paper we have analysed data derived from a total of nine published reports of controlled trials in which an oxytocic drug was compared with either a placebo or no routine prophylactic. Oxytocic drugs used routinely appear to reduce the risk of postpartum haemorrhage by about 40% (typical odds ratio 0.57, 95% confidence interval 0.44-0.73) implying that for every 22 women given such an oxytocic, one postpartum haemorrhage could be prevented. The available data are insufficient to assess the possible effects of this policy on the incidence of retained placenta, hypertension and other possible adverse effects.

Clinical Trials as Topic↗
PubMed1988

Choice of oxytocic preparation for routine use in the management of the third stage of labour: an overview of the evidence from controlled trials.

Prophylactic use of oxytocics reduces the risk of postpartum haemorrhage by about 40%. The analysis presented in this paper assesses which oxytocic preparation is associated with the least risk of postpartum haemorrhage and examines the relative effects of different preparations on the length of the third stage, the risk of manual removal of the placenta, blood pressure and other side-effects. A mixture of oxytocin and ergometrine (Syntometrine) appears to be the safest and most effective prophylactic of the alternatives which have been compared, but the quality of the evidence is not satisfactory. There is scope for a randomized comparison of Syntometrine with oxytocin to obtain unbiased and more precise estimates of their relative effects on postpartum haemorrhage, blood pressure and unpleasant side-effects.

Clinical Trials as Topic↗
PubMed1988

Beta-mimetics in preterm labour: an overview of the randomized controlled trials.

Controversy continues about the use of beta-mimetic drugs in preterm labour. One reason for this is that the adequately controlled trials of these drugs have all been small and have thus provided very imprecise estimates of their effects. We have therefore conducted a 'meta-analysis' using data relating to 890 women who participated in the 16 methodologically acceptable controlled trials of these agents in the treatment of preterm labour. This analysis demonstrates an unequivocal effect of beta-mimetic tocolytic administration in delaying delivery, and this is reflected in a reduction in the frequency of preterm birth and low birthweight. However, no beneficial effect of this treatment on perinatal mortality or severe neonatal respiratory disorders could be detected.

Adrenergic beta-Agonists↗
PubMed1987

Reported management of threatened miscarriage by general practitioners in Wessex.

Questionnaires were sent to all 1432 general practitioners in the Wessex region to obtain information about their current management of bleeding in early pregnancy. A total of 1290 (90%) returned completed questionnaires. These showed widely varying views about the prognostic importance of particular symptoms and physical signs and about elements of management. Although 96% of the respondents prescribed bed rest more or less routinely for heavy bleeding in early pregnancy, only 17% felt it was mandatory, and 32% admitted that they did not believe it affected the outcome. Of the 13% of respondents who prescribed progestogens for threatened miscarriage, most did so on the advice of their local obstetrician. Seventeen per cent of the doctors always admitted women with apparently complete miscarriages to hospital. Twenty nine per cent of the respondents never gave anti-D immunoglobulin to rhesus negative women after a complete miscarriage. Bleeding in early pregnancy is a common problem and more research is required to improve management, particularly the assessment of fetal viability.

Abortion, Threatened↗
PubMed1987

Antecedents and outcome of very early neonatal seizures in infants born at or after term.

Recent experimentally derived evidence has confirmed earlier suggestions that seizures which occur within 48 h of birth in babies born at or later than 37 completed weeks gestation are particularly likely to reflect intrapartum asphyxia. We have compared 54 cases of such seizures with 41,090 controls in a geographically defined population. Nulliparity, hydramnios, post-term pregnancy, oxytocin augmentation of labour, abnormalities of fetal heart rate and/or meconium-stained amniotic fluid, prolonged second stage of labour, emergency caesarean section, assisted vaginal delivery, low Apgar score and resuscitation at delivery and subsequent ventilatory support were all statistically significantly more common among cases than among controls. Five of the 54 babies who developed seizures died within 28 days of birth and 11 of the 49 survivors had an impairment diagnosed by 3 years of age which was usually associated with some degree of cerebral palsy. Comparison of the frequency of antecedent perinatal risk factors in the seizure babies who died, those who survived with disabilities and normal survivors failed to reveal any clear pattern.

Cerebral Palsy↗
PubMed1987

The Newbury Maternity Care Study: a randomized controlled trial to assess a policy of women holding their own obstetric records.

To assess a policy of women holding and thus having constant access to their own obstetric records, 290 women attending a peripheral consultant clinic in Newbury, West Berkshire, were randomly allocated to hold either their full case notes, or the more usual co-operation card. Women holding their full records were significantly more likely to feel in control of their antenatal care (rate ratio 1.45; 95% confidence interval 1.08-1.95) and to feel it was easier to talk to doctors and midwives (rate ratio 1.73; 95% confidence interval 1.16-2.59). No other beneficial effects were detected. Asked about their preferences for any subsequent pregnancies, women holding their own records in the index pregnancy were more likely to say they would prefer to hold the same kind of record again in a subsequent pregnancy than were women holding a co-operation card (rate ratio 1.56; 95% confidence interval 1.34-1.81). There was no evidence of negative effects. In particular, women holding their case notes did not feel more anxious than co-operation card holders. The policy of women holding their notes resulted in savings in clerical time, without evidence of an increase in the rate of lost notes.

Clinical Trials as Topic↗
PubMed1986

The Oxford Database of Perinatal Trials: developing a register of published reports of controlled trials.

A database of perinatal trials is currently being established to provide a resource for reviews of the safety and efficacy of interventions used in perinatal care and to foster cooperative and coordinated research efforts in the perinatal field. The database will ultimately comprise four main elements: a register of published reports of trials; a register of unpublished trials; a register of ongoing and planned trials; and data derived from pooled overviews (meta-analyses) of trials. This article describes the development of the first of these four elements.

Clinical Trials as Topic↗
PubMed1986

Follow up of babies delivered in a randomized controlled comparison of vacuum extraction and forceps delivery.

Babies delivered in a randomized controlled comparison of vacuum extraction vs. forceps delivery were reassessed at 9 months of age. There were no statistically significant differences between the two groups as regards head circumference, weight, or head circumference to weight ratio, nor in the results of hearing and vision tests. The reasons for hospital readmission, pediatric follow-up and parents' and health visitors' worries appeared to be unrelated to the mode of delivery in nearly all cases. The finding in the original trial that neonatal jaundice was more common following vacuum extraction was reinforced by an additional case of jaundice in the vacuum extractor group which had necessitated readmission to hospital.

Child Development↗
PubMed1986

Secular changes in rehospitalization of very low birth weight infants.

Neonatal survival among very low birth weight infants (less than 1,500 g) has improved dramatically during the last decade. Concern about the quality of life among these survivors has focused mainly on the prevalence of severe motor, sensorineural, and intellectual impairment. This study examined the possible effects of increasing survival on less serious morbidity as evidenced by hospital readmission patterns. The experience of VLBW survivors in a geographically defined population has been compared with that of a randomly selected group of heavier infants. As VLBW infant survival rates improved from 35% to 48% between 1968 to 1972 and 1974 to 1978, the rehospitalization rate before 2 years of age increased from 22% to 27%. In contrast, among heavier infants, rehospitalization rates decreased from 9.8% to 8.9%. The relative risk of readmission associated with VLBW thus increased from 2.2 to 3.0. Although this increase in the overall relative risk of rehospitalization in VLBW infants was not statistically significant, there was a dramatic and statistically significant increase in the relative risk of being readmitted because of structural defects (particularly hernias). Overall, there was a marked decline in the number of days spent in the hospital in both birth weight groups.

Congenital Abnormalities↗