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Biomedical subjects

C Nimrod

Publications and source records attributed to C Nimrod.

At least 19 recordsLinked to original sources
PubMed2005

Haloacetic acids in drinking water and risk for stillbirth.

BACKGROUND: Trihalomethanes (THMs) occurring in public drinking water sources have been investigated in several epidemiological studies of fetal death and results support a modest association. Other classes of disinfection by-products found in drinking water have not been investigated. AIMS: To investigate the effects of haloacetic acid (HAA) compounds in drinking water on stillbirth risk. METHODS: A population based case-control study was conducted in Nova Scotia and Eastern Ontario, Canada. Estimates of daily exposure to total and specific HAAs were based on household water samples and questionnaire information on water consumption at home and work. RESULTS: The analysis included 112 stillbirth cases and 398 live birth controls. In analysis without adjustment for total THM exposure, a relative risk greater than 2 was observed for an intermediate exposure category for total HAA and dichloroacetic acid measures. After adjustment for total THM exposure, the risk estimates for intermediate exposure categories were diminished, the relative risk associated with the highest category was in the direction of a protective effect, and all confidence intervals included the null value. CONCLUSIONS: No association was observed between HAA exposures and stillbirth risk after controlling for THM exposures.

Acetates↗
PubMed1998

Sonographic evaluation of intervillous flow in early pregnancy: use of echo-enhancement agents.

The uteroplacental circulation of the cynomolgus monkey was examined in early pregnancy using a high-resolution ultrasound scanner. Intravenous injection of an echo-contrast agent, Albunex (sonicated albumin), was used to enhance the color Doppler images obtained. The flow of blood into and out of the intervillous compartment was readily assessed and quantified using pulsed and color Doppler. Flow within the intracotyledonary space was pulsatile and indicative of a low-resistance system. Flow within the decidual veins was non-pulsatile. The use of echo-contrast agents may assist in the determination of intervillous flow in human pregnancy at a correspondingly early stage.

Albumins↗
PubMed1998

Evaluation of a midwifery birthing center in the Canadian north.

An evaluation of a midwife-operated community birthing center was conducted to identify whether it would be safe, cost-effective, and psychologically and socially satisfying for Inuit women in one community in the Northwest Territories. Two nurse-midwives provided antenatal and postnatal care to all pregnant women and delivered those designated as 'low risk' for complications. Another community similar in size but with no community birthing was used for comparison of the three indices. Data were gathered on reproductive histories and pregnancy risk profiles of all women giving birth in a one-year period. The financial costs were calculated for those women transferred out to hospital for delivery and compared with those who stayed in the community. Pregnant women and their partners in both communities, health staff, and community members were interviewed for their feelings and concerns about the birthing services. Preliminary findings suggest that with experienced midwives community births are safe. A minimum of 25 births is required in the community for this project to be cost effective. The women who had their infants in the community expressed satisfaction for a number of reasons.

Arctic Regions↗
PubMed1997

The role of reduced ear size in the prenatal detection of chromosomal abnormalities.

A prospective ultrasound study was performed between 18 and 38 weeks' gestation on 29 fetuses in a high-risk population, defined by the presence of structural anomalies, in order to investigate the usefulness of fetal ear measurements in the prenatal prediction of chromosomal abnormality. The prevalence of abnormal chromosomes was 34 per cent. The sensitivity (SE), specificity (SC), positive predictive values (PPV), and negative predictive values (NPV) of ear length for the detection of chromosomal abnormality were 80, 84.2, 72.7 and 88.9 per cent. The SE, SC, PPV, and NPV of ear width were 40, 94.7, 80 and 75 per cent. Fetal ear measurements may be a useful adjunct to the various ultrasound parameters in the prenatal detection of chromosome abnormality in a high-risk population of fetuses with structural anomaly(ies).

Adolescent↗
PubMed1997

Determination of intervillous flow in early pregnancy.

The process of placentation in the macaque has been extensively studied and found to resemble closely that observed in the human. In this model, histopathologically, intervillous flow is anticipated from week 3 post-conception. We set out to document the nature and onset of intervillous flow in the macaque in vivo using colour Doppler imaging (CDI), colour Doppler energy (CDE) and pulsed-wave Doppler (PWD). Pregnant females were assessed between 15-50 days gestation (term = 165 days) with an Acuson 128/XP10 high-resolution ultrasound scanner, using a 7-MHz linear array probe. The placenta, subjacent decidua and myometrium were assessed using CDI and CDE. Specific regions of flow were interrogated using PWD; the resulting flow velocity waveforms were stored and quantified using conventional Doppler indices. B-mode sonography was able to demonstrate the well-defined placental-decidual interface observed in this species; CDI and CDE clearly visualized the uteroplacental vasculature. Spiral arteries were followed to their point of discharge into the intervillous space, and PWD at these sites obtained a characteristic flow velocity waveform. The indices obtained confirmed a flow of low resistance and pulsatility throughout the gestation studied. Flow within the intervillous space was noted from day 20 of gestation.

Animals↗
PubMed1996

Evaluation of a fetal monitoring education program.

OBJECTIVE: To evaluate the effectiveness of a fetal monitoring education program in increasing nurses' knowledge and clinical skills. DESIGN: Multicenter randomized control trial. SETTING: Twelve hospitals in eastern Ontario, Canada. PARTICIPANTS: One hundred nine volunteer registered nurses randomly assigned, within each hospital, to an experimental (n = 47) or control (n = 62) group. Ninety-six nurses (40 in the experimental group and 56 in the control group) completed the 6-month follow-up (88% retention). INTERVENTIONS: The experimental group participated in a 1-day fetal monitoring workshop and a review session 6 months later. MAIN OUTCOME MEASURES: Performance on a 45-item knowledge test and a 25-item skills checklist. The passing score was at least 75% correct on each test. RESULTS: The percentage of nurses in the experimental group passing both the knowledge and the clinical skills tests after the workshop was significantly higher (p < 0.01) than that of the nurses in the control group: 68.1% versus 6.5%, respectively. A large difference between the groups remained at the 6-month follow-up (experimental, 45%; control, 6.5%). The performance of the nurses in the experimental group improved to an 85% pass rate after they attended the 6-month review session. CONCLUSION: This comprehensive, research-based program is effective in increasing fetal monitoring knowledge and clinical skills.

Analysis of Variance↗
PubMed1995

Doppler sonographic studies on the ophthalmic and central retinal arteries in the gravid woman.

The aim of this study was to establish normative data as gestation advances for pulsed Doppler evaluation of both the ophthalmic artery and the central retinal artery. After measuring intraocular pressure and blood pressure, pulsed Doppler ultrasonographic examination was performed on the ophthalmic and central retinal arteries in both eyes of 125 normal pregnant women. Nomograms, with 95% prediction intervals, have been generated for the Doppler indices, reflecting blood flow in both the ophthalmic and the central retinal arteries. The use of this technique in the management of pregnancy induced hypertension can now be better evaluated.

Blood Pressure↗
PubMed1993

The need for a community-wide approach to promote healthy babies and prevent low birth weight.

A community-wide approach offers a potentially more effective way to promote healthy babies in healthy families and to prevent low birth weight. It can address the many factors associated with preterm birth and intrauterine growth restriction, the need to include all members of the community in effecting meaningful change in the incidence rate of adverse outcomes and the development of an effective mechanism to plan and coordinate the delivery of programs. Physicians have an essential role to play in this approach. The evaluation of such a program would complement current biomedical research on the prevention of preterm birth and intrauterine growth restriction. The work for this paper was supported by the Community Health Research Unit, funded by the Ontario Ministry of Health.

Community Health Services↗
PubMed1993

Birthing experience of adolescents at the Ottawa General Hospital Perinatal Centre.

OBJECTIVE: To study the experiences of prenatal care, prenatal classes and birthing among adolescents. DESIGN: Anonymous self-report questionnaire survey. SETTING: Ottawa General Hospital Perinatal Centre. PATIENTS: A total of 100 adolescents (aged less than 20 years) and 100 control subjects (aged over 19 years) who gave birth at the Perinatal Centre from June 1989 to August 1990. MAIN OUTCOME MEASURES: Prenatal experiences, attendance at prenatal classes, experiences in labour and delivery, postpartum care. RESULTS: Only 26% of the adolescent patients sought prenatal care in the first trimester, and only 27% attended prenatal classes, as compared with 87% and 91% of the control subjects (p < 0.001). Most of the adolescents felt uncomfortable in the same waiting room as adult women. During labour and delivery 50% of the adolescents had their mothers with them for support, whereas 83% of the adults had their husbands with them (p < 0.001). Over half (59%) of the adolescents stated that they were not prepared for labour and delivery, as compared with 26% of the adults (p < 0.001). Of the adolescents 85% opted to care for their babies after birth. CONCLUSION: Pregnant adolescents do not avail themselves adequately of the medical and psychosocial services available to them through the health care system. Our findings suggest features of prenatal clinics that would make them attractive and accessible to such patients.

Adolescent↗
PubMed1993

Fetal tumors associated with hydrops: the role of the pediatric surgeon.

Fetal tumors are being diagnosed with increasing frequency and great accuracy by antenatal ultrasound. High-output cardiac failure and hydrops indicate fetal distress. Management may be limited by the gestational age of the fetus. Our experience with three fetal tumors demonstrates the dilemma with respect to timing of delivery and prognosis. Following the diagnosis of a large sacrococcygeal tumor, a 22-week-gestation fetus became hydropic and died. Another fetus with a rapidly growing posterolateral chest wall mass required cesarean section delivery at 29 weeks gestation. Postnatal course was complicated by pulmonary hypoplasia, intratumoral hemorrhage, and death. The third fetus had an enlarging tumor in the right lobe of the liver. Poor biophysical profile and mild hydrops necessitated cesarean section delivery at 34 weeks. Right hepatic lobectomy was performed and the infant was subsequently discharged home at one month of age. The deleterious effects of the fetal tumor and the need for its removal have to be carefully weighed against the ability of the fetus to survive postnatally.

Adult↗
PubMed1992

Transverse cerebellar diameter in twin gestations.

OBJECTIVE: The purpose of this study was to evaluate the significance of transverse cerebellar diameter measurements in twin pregnancies. STUDY DESIGN: A prospective, cross-sectional ultrasonographic study was done on 329 normal singleton fetuses and 47 normal twin pairs. Fetal biometric measurements including biparietal diameter, head circumference, abdominal circumference, femur length, and transverse cerebellar diameter were compared between concordant (n = 13) and discordant (n = 11) twins. RESULTS: (1) There was no significant difference in transverse cerebellar diameter measurements between normal singleton and twin gestations. (2) There was no significant difference in transverse cerebellar diameter measurements in each twin pair. (3) Transverse cerebellar diameter was unaffected by the chorionicity or discordancy. (4) Predicted gestational age by transverse cerebellar diameter nomogram for singletons provided satisfactory correlation for twins. CONCLUSION: Transverse cerebellar diameter may be a useful predictor of gestational age and may be independent of discordant growth in twins.

Biometry↗
PubMed1992

Ultrasonographic measurements of fetal ear.

OBJECTIVE: To establish nomograms of fetal ear measurements. Newborns with trisomies have smaller ears than the normal population. This observation led us to believe that ear measurements might be useful in the antenatal prediction of fetuses with abnormal karyotypes. METHODS: Fetal ear length and width were obtained ultrasonographically in 124 normal singleton pregnancies between 18-42 weeks' gestation. Regression analyses were used to create the nomograms. RESULTS: Linear relationships were found between ear length and width and gestational age (r = 0.956 and 0.898, respectively). In addition, there were significant correlations between ear measurements and biparietal diameter, head circumference, abdominal circumference, and femur length. The ear width-length ratio and the biparietal diameter-ear length ratio were independent of gestational age. CONCLUSION: These normative data may be helpful in the antenatal prediction of chromosomal abnormalities.

Down Syndrome↗
PubMed1992

Multiple births: trends and patterns in Canada, 1974-1990.

This paper examines Canadian trends and patterns in multiple births in relation to total confinements, singleton births, maternal age, parity, gestational age and birth weight using vital statistics from 1974 to 1990. Multiple-birth rates in Canada increased from 912.8 to 1,058.9 per 100,000 confinements between 1974 and 1990. The increase is especially noticeable for women over 30. The rate of triplet and higher-order births increased from 8.3 to 21.7 per 100,000 confinements between 1974 and 1990. The proportion of multiple-birth babies that were pre-term (< 37 weeks gestation period) increased from 32.8% in 1974 to 45.8% in 1990. Factors associated with the increase in multiple births may include the use of assisted pregnancy techniques, and the fact that women aged 30 and older, who are at higher risk of a multiple birth, and who postponed their child bearing, have increased their fertility. The sharp increase in multiple-birth rates has implications for maternal and child health and health care costs.

Adolescent↗
PubMed1989

Simultaneous use of Doppler ultrasound and electromagnetic flow probes in fetal flow assessment.

A placental embolization model in the fetal lamb was used to examine the relationship between acute and chronic alternations in placental vascular resistance and changes in flow velocity waveforms as measured by Doppler and electromagnetic flow probes. The peak systolic to end-diastolic (S/D) ratio measured by these techniques was .885 and the correlations between Doppler S/D ratio and placental vascular resistance in the acute and chronic situations were .86 and .339, respectively. This preliminary data suggest that flow velocity waveforms are independent of the method used and that remarkable differences occur in the placental microcirculation during acute and chronic embolization.

Animals↗
PubMed1989

Duplex ultrasonography of the fetal aorta, umbilical artery, and placental arcuate artery throughout normal human pregnancy.

A cross-sectional duplex study of blood flow in the fetal aorta, umbilical artery, and arcuate arteries of 111 normal subjects was performed once at between 20 and 42 weeks gestation. Peak systolic velocity, end-diastolic velocity, mean velocity, and volume flow were measured in the fetal aorta, and systolic to diastolic (S/D) ratios were measured in all three vessels. Velocities show an inverse exponential (Y = Exp [1/X x B + C]) increase with gestational age, reaching a plateau just before term, while S/D ratios in the aorta and umbilical arteries show a linear decrease. Such findings are at variance with some published data. Our results suggest a reduction in fetal placental resistance at term and provide useful data concerning normal fetal and placental circulations.

Aorta↗