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Biomedical subjects

J P Neilson

Publications and source records attributed to J P Neilson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ultrasound for fetal assessment in early pregnancy.

BACKGROUND: Advantages of early pregnancy ultrasound screening are thought to be more accurate calculation of gestational age, earlier identification of multiple pregnancies, and diagnosis of non-viable pregnancies and certain fetal malformations. OBJECTIVES: The objective of this review was to assess the use of routine (screening) ultrasound compared with the selective use of ultrasound in early pregnancy (ie before 24 weeks). SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (up to July 1998) were searched. SELECTION CRITERIA: Adequately controlled trials of routine ultrasound imaging in early pregnancy. DATA COLLECTION AND ANALYSIS: One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Nine trials were included. The quality of the trials was generally good. Routine ultrasound examination was associated with earlier detection of multiple pregnancies (twins undiagnosed at 26 weeks, odds ratio 0.08, 95% confidence interval 0.04 to 0.16) and reduced rates of induction of labour for post-term pregnancy (odds ratio 0. 61, 95% confidence interval 0.52 to 0.72). There were no differences detected for substantive clinical outcomes such as perinatal mortality (odds ratio 0.86, 95% confidence interval 0.67 to 1.12). Where detection of fetal abnormality was a specific aim of the examination, the number of terminations of pregnancy for fetal anomaly increased. REVIEWER'S CONCLUSIONS: Routine ultrasound in early pregnancy appears to enable better gestational age assessment, earlier detection of multiple pregnancies and earlier detection of clinically unsuspected fetal malformation at a time when termination of pregnancy is possible. However the benefits for other substantive outcomes are less clear.

Female↗
PubMed2000

Symphysis-fundal height measurement in pregnancy.

BACKGROUND: In many settings, symphysis-fundal height measurement has replaced clinical assessment of fetal size by abdominal palpation because the latter has been reported to perform poorly. OBJECTIVES: The objective of this review was to assess the effects of routine use of symphysis-fundal height measurements (tape measurement of the distance from the pubic symphysis to the uterine fundus) during antenatal care on pregnancy outcome. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register was searched. SELECTION CRITERIA: Acceptably controlled trials comparing symphysis-fundal height measurement with assessment by abdominal palpation alone. DATA COLLECTION AND ANALYSIS: One reviewer assessed trial quality and extracted data. MAIN RESULTS: One trial involving 1639 women was included. No differences were detected in any of the outcomes measured. REVIEWER'S CONCLUSIONS: There is not enough evidence to evaluate the use of symphysis-fundal height measurements during antenatal care.

Anthropometry↗
PubMed2000

Routine doppler ultrasound in pregnancy.

BACKGROUND: Doppler ultrasound study of umbilical artery waveforms helps identify the compromised fetus in 'high risk' pregnancies and, therefore, deserves assessment as a screening test in 'low risk' pregnancies. One of the main aims of routine antenatal care is to identify the 'at risk' fetus in order to apply clinical interventions which could result in reduced perinatal morbidity and mortality. OBJECTIVES: To assess the effects on obstetric practice and pregnancy outcome of routine Doppler ultrasound in unselected and low risk pregnancies. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Specialised Register of Controlled Trials and the Cochrane Controlled Trials Register were searched. Date of last search: September 1999 SELECTION CRITERIA: Acceptably controlled trials of routine Doppler ultrasound (umbilical circulation and/or uterine circulation) in unselected or low risk pregnancies. DATA COLLECTION AND ANALYSIS: Both reviewers assessed trial quality and extracted data. Authors of two trials were contacted for additional information. MAIN RESULTS: Five trials were included which recruited 14,338 women. The methodological quality of the trials was generally good. Based on existing evidence, routine Doppler ultrasound examination in low risk or unselected populations did not result in increased antenatal, obstetric and neonatal interventions, and no overall differences were detected for substantive short term clinical outcomes such as perinatal mortality. There is no available evidence to assess the effect on substantive long term outcomes such as childhood neurodevelopment. There is no available evidence to assess maternal outcomes, particularly psychological effects. In two studies there were unexpected findings suggesting possible harmful effects, but the explanation for this is not clear, and further evaluation regarding the safety of Doppler ultrasound is required. REVIEWER'S CONCLUSIONS: Based on existing evidence, routine Doppler ultrasound in low risk or unselected populations does not confer benefit on mother or baby. Future research should be powerful enough to address small changes in perinatal outcome, and should include evaluation of maternal psychological effects, long term outcomes such as neurodevelopment, and issues of safety.

Female↗
PubMed2000

Routine ultrasound in late pregnancy (after 24 weeks gestation).

BACKGROUND: Diagnostic ultrasound is used selectively in late pregnancy where there are specific clinical indications. However, the value of routine late pregnancy ultrasound screening in unselected populations is controversial. The rationale for such screening would be the detection of clinical conditions which place the fetus or mother at high risk, which would not necessarily have been detected by other means such as clinical examination, and for which subsequent management would improve perinatal outcome. OBJECTIVES: To assess the effects on obstetric practice and pregnancy outcome of routine late pregnancy ultrasound, defined as greater than 24 weeks gestation, in women with either unselected or low risk pregnancies. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Specialised Register of Controlled Trials and the Cochrane Controlled Trials Register were searched. SELECTION CRITERIA: All acceptably controlled trials of routine ultrasound in late pregnancy (defined as after 24 weeks). DATA COLLECTION AND ANALYSIS: The principal reviewer assessed trial quality and extracted data, under supervision of the co-reviewer. MAIN RESULTS: Seven trials recruiting 25,036 women were included. The quality of trials overall was satisfactory. There was no difference in antenatal, obstetric and neonatal intervention or morbidity in screened versus control groups. Routine late pregnancy ultrasound was not associated with improvements in overall perinatal mortality. Placental grading as an adjunct to third trimester examination scan was associated with a significant reduction in the stillbirth rate in the one trial that assessed it. There is a lack of data with regard to long term substantive outcomes such as neurodevelopment. There is a lack of data on maternal psychological effects. REVIEWER'S CONCLUSIONS: Based on existing evidence, routine late pregnancy ultrasound in low risk or unselected populations does not confer benefit on mother or baby. There is a lack of data about the potential psychological effects of routine ultrasound in late pregnancy, and the effects on both short and long term neonatal and childhood outcome. Placental grading in the third trimester may be valuable, but whether reported results are reproducible remains to be seen, and future research of late pregnancy ultrasound should include evaluation of placental textural assessment.

Female↗
PubMed2000

Interventions for suspected placenta praevia.

BACKGROUND: Because placenta praevia is implanted unusually low in the uterus, it may cause major, and/or repeated, antepartum haemorrhage. The traditional policy of care of women with symptomatic placenta praevia includes prolonged stay in hospital and delivery by caesarean section. OBJECTIVES: To assess the impact of any clinical intervention applied specifically because of a perceived likelihood that a pregnant woman might have placenta praevia. SEARCH STRATEGY: A comprehensive electronic search was performed to identify relevant literature. Searched databases included the Trials Register maintained by the Cochrane Pregnancy and Childbirth Group, and the Cochrane Controlled Clinical Trials Register. SELECTION CRITERIA: Any controlled clinical trial that has assessed the impact of an intervention in women diagnosed as having, or being likely to have, placenta praevia. DATA COLLECTION AND ANALYSIS: Data were extracted from the three identified trial reports, unblinded, by the author without consideration of results. MAIN RESULTS: Two comparisons could be made - home versus hospitalisation and cervical cerclage versus no cerclage. Both were associated with reduced lengths of stay in hospital antenatally. Otherwise, there was little evidence of any clear advantage or disadvantage to a policy of home versus hospital care. Cervical cerclage may reduce the risk of delivery before 34 weeks, or the birth of a baby weighing less than 2 kg or having a low 5 minute Apgar score. In general, these possible benefits were more evident in the trial of lesser methodological quality. REVIEWER'S CONCLUSIONS: There are insufficient data from trials to recommend any change in clinical practice. Available data should, however, should encourage further work to address the safety of more conservative policies of hospitalisation for women with suspected placenta praevia, and the possible value of insertion of a cervical suture.

Female↗
PubMed2000

Mifepristone for induction of labour.

BACKGROUND: The steroid hormone, progesterone, inhibits contractions of the uterus. Antiprogestins (including mifepristone) have been developed to antagonise the action of progesterone, and these have a recognised role in medical termination of early or mid-pregnancy. Animal studies have suggested that mifepristone may also have a role in inducing labour in late pregnancy. OBJECTIVES: To determine the effects of mifepristone for third trimester cervical ripening or induction of labour. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register, and reference lists of relevant papers. SELECTION CRITERIA: Selection criteria included: (1) clinical trials comparing mifepristone used for third trimester cervical ripening or labour induction with placebo/no treatment or other labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. Data were extracted by the reviewer and, independently, by a colleague. MAIN RESULTS: Seven trials, that recruited 594 women, are included. All trials compared mifepristone with placebo, except for one that compared mifepristone with no treatment. Compared to placebo, mifepristone treated women were less likely to have an unfavourable cervix at 48 hours (relative risk [RR] 0.36, 95% confidence intervals [CI] 0.2-0.63) or 96 hours (RR 0.39, 95% CI 0.23-0.66). Mifepristone treated women were more likely to have delivered within 48 and 96 hours of treatment than were placebo treated/no treatment women - 48 hours: RR 2.82, 95% CI 1.82-4.36; 96 hours: RR 3.40, 95% CI 1.96-5.92. Mifepristone treated women were less likely to undergo caesarean section (RR 0.71, 95% CI 0.53-0.95). There is little information about fetal outcome, although there was no evidence that neonatal hypoglycaemia might be more common after exposure to mifepristone. Similarly, there is little information about maternal side-effects although some nausea and vomiting was reported in one trial. REVIEWER'S CONCLUSIONS: There is insufficient information available from clinical trials to support the use of mifepristone to induce labour. However, available data do show that mifepristone is better than placebo at ripening the cervix, and inducing labour. There is evidence of a possible reduction in the incidence of caesarean section following mifepristone treatment (compared to placebo) that would justify further trials. We found no trials that compared mifepristone with alternative methods of inducing labour e.g. prostaglandins.

Clinical Trials as Topic↗
PubMed1998

Evidence-based intrapartum care: evidence from the Cochrane library.

OBJECTIVE: To describe the concepts on which systematic reviews of randomized controlled trials are based, and to explore the evidence for effectiveness of clinical interventions during labor and delivery. METHODS: Review of systematic reviews of interventions during labor and delivery, published in the Cochrane Library. RESULTS: Some commonly applied clinical interventions are supported by evidence; others are not. CONCLUSION: It is possible to classify interventions during labor and delivery according to their effectiveness, to improve clinical care, identify priorities where resources are scarce, and help set clinical research agendas.

Episiotomy↗
PubMed1998

The relationship between asymptomatic human immunodeficiency virus infection and the prevalence and severity of anemia in pregnant Malawian women.

The relationship between asymptomatic human immunodeficiency virus (HIV) infection and blood hemoglobin (Hb) concentration was examined in anemic pregnant women from a population with high prevalence of both anemia (60%) and HIV seropositivity (30%). Sera from 155 pregnant women with Hb levels < 10.5 g/dL were tested for HIV status, C-reactive protein (CRP), vitamin B12, retinol, and folate levels. The observed prevalence of HIV seropositivity in the group of women with anemia was 47.1% (95% confidence interval=39.2-55.0%). This is significantly higher than the HIV prevalence in the whole population (30.1%; P < 0.001). Median Hb values in HIV-seropositive and -seronegative women with anemia were 8.40 g/dL and 8.95 g/dL, respectively. Serum retinol, vitamin B12, and folate levels were not significantly different in the HIV-seropositive and -seronegative groups. In women who were HIV-seropositive with normal levels of CRP, a median decrease in Hb of 0.4 g/dL was observed. For those with serum CRP levels > 25 mg/l, the median decrease in Hb was 0.7 g/dL. Results indicate that asymptomatic HIV infection is associated with increased prevalence and severity of anemia in pregnancy in this population.

Anemia↗
PubMed1996

Interleukin-6, interferon-gamma, interleukin-8, and granulocyte-macrophage colony stimulating factor levels in human amniotic fluid at term.

Cytokines contribute to the maintenance of successful pregnancy and have also been implicated in the initiation of labour. This study has examined those cytokines which may be involved in normal term parturition. IL-6, IFN-gamma, IL-8 and GM-CSF levels were measured by ELISA in samples of amniotic fluid, peripheral and uterine venous blood plasma, and umbilical artery blood plasma from non-labouring women undergoing elective caesarean section at term and from women in spontaneous labour. IFN-gamma and IL-6 were detected only in amniotic fluid and not in blood plasma samples, unlike IL-8 which was found in all amniotic fluid and plasma samples from both labouring and non-labouring women; GM-CSF was undetectable in all samples examined. Levels of IL-6 were significantly raised in the amniotic fluid of women in labour compared with the control group (P = 0.008). IFN-gamma was detected in the amniotic fluid of both labouring women and the control group, and there was also a significant correlation (P = 0.003) between IFN-gamma and IL-6 levels in individual amniotic fluid samples. The presence of both IFN-gamma and IL-8 in amniotic fluid, as well as IL-6, suggests these cytokines are involved in important immunobiological events relevant to the latter half of gestation.

Adult↗
PubMed1996

The current status of Doppler sonography in obstetrics.

Searches for clinical applications of Doppler ultrasound in fetomaternal medicine continue. Currently, there are three main areas of interest: Doppler velocimetry of the umbilical artery, uterine artery and the fetal circulation (cerebral and venous blood flow studies). Evidence from randomized trials suggests that if women with suspected intra-uterine growth retardation or pre-eclampsia are offered Doppler studies of the umbilical artery, a clinically important reduction in perinatal mortality may be expected. On the other hand, screening of low-risk women either by umbilical artery Doppler or uterine artery Doppler is unlikely to be cost-effective. The study of other fetal vessels provides a fascinating insight into vascular changes that occur in fetal compromise, but it is not known whether the use of these tests will actually reduce perinatal mortality and morbidity. None of the Doppler indices used so far, including the middle-cerebral artery to umbilical artery ratio, has been able to match the performance characteristics of umbilical artery Doppler. Until clear evidence emerges on its benefit or otherwise, comprehensive fetal assessment by Doppler ultrasound should be used for research purposes only and results of these tests should not be used to guide clinical practice.

Clinical Trials as Topic↗
PubMed1995

Doppler ultrasonography in high-risk pregnancies: systematic review with meta-analysis.

OBJECTIVE: Our objective was to review all available (published and unpublished) randomized controlled trials of Doppler ultrasonography of the umbilical artery in high-risk pregnancies. STUDY DESIGN: Only completed randomized controlled trials were included and reviewed according to the prespecified protocol. Data were sought for 24 prespecified perinatal outcomes. All meta-analyses were based on the "intention to treat." Primary outcome was defined as perinatal death (any death in utero or postnatally recorded during duration of individual randomized controlled trial). Reported perinatal outcomes that were not prespecified were meta-analyzed on a post hoc basis. RESULTS: Twenty randomized controlled trials of Doppler ultrasonography were identified; 12 fulfilled the prespecified criteria. Meta-analysis shows a significant reduction in the number of antenatal admissions (44%, 95% confidence interval 28% to 57%), inductions of labor (20%, 95% confidence interval 10% to 28%), and cesarean sections for fetal distress (52%, 95% confidence interval 24% to 69%) in the Doppler group and that the clinical action guided by Doppler ultrasonography reduces the odds of perinatal death by 38% (95% confidence interval 15% to 55%). The reduction in perinatal deaths was also observed in five mortality subgroups (i.e., stillbirths, neonatal deaths, deaths of normally formed babies, normally formed stillbirths, and deaths of normally formed neonates). Post hoc analyses revealed a statistically significant reduction in elective delivery, intrapartum fetal distress, and hypoxic encephalopathy in the Doppler group. CONCLUSION: There is now compelling evidence that women with high-risk pregnancies, including preeclampsia and suspected intrauterine growth retardation, should have access to Doppler ultrasonographic study of umbilical artery waveforms.

Delivery, Obstetric↗
PubMed1995

Interleukin-6 in amniotic fluid obtained at forewater amniotomy compared with hindwater samples in women in spontaneous labour.

Using an aseptic technique, samples of amniotic fluid were obtained from the forewaters and hindwaters of fifteen women in spontaneous labour with a deeply engaged fetal head. Prior to sampling, a cervical swab was obtained to exclude infection and in 10 cases samples of amniotic fluid were sent for microscopy and culture. Forewater samples were obtained using a pudendal block needle. Hindwater samples were obtained after membrane rupture by inserting an intra-uterine pressure catheter. Batch assay for interleukin-6 (IL-6) concentrations was performed using a specific ELISA. The levels of IL-6 in forewater samples of amniotic fluid were significantly higher than those found in hindwater samples (t = 3.65, P < 0.002). This suggests that either the production of IL-6 as a result of stimulation by its cytokine 'effectors' is greater at this site, or that the loss or metabolism of IL-6 in the forewaters is less than that in the hindwaters. The concentration of IL-6 parallels the reported levels of PGE2, and it is therefore likely that if IL-6 is involved in the mechanism of labour it acts through the effects of the resultant PGE2 release.

Adolescent↗