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Biomedical subjects

L Dodds

Publications and source records attributed to L Dodds.

At least 19 recordsLinked to original sources
PubMed2001

Causes and consequences of recent increases in preterm birth among twins.

OBJECTIVE: To examine the causes and consequences of the recent increase in preterm birth among twins. METHODS: We studied all twin births among residents of the province of Nova Scotia, Canada, between 1988 and 1997. Rates of preterm birth, preterm labor induction, preterm cesarean, small-for-gestational age (SGA), respiratory distress syndrome (RDS), stillbirth, perinatal mortality, and infant mortality were compared between past and more recent years. Changes in perinatal mortality were examined using logistic regression to adjust for the effects of other determinants. RESULTS: The study included 2516 twin births (73 stillbirths and 2443 live births). The rate of preterm birth increased from 42.3% in 1988-1992 to 48.2% of twin live births in 1993-1997 (14% increase, P =.04). Twin live births born after preterm labor induction increased from 3.5% in 1988-1989 to 8.6% in 1996-1997 (P for trend =.007). Of live births between 34 and 36 weeks' gestation, the proportion born SGA decreased from 17.5% in 1988-1992 to 9.2% in 1993-1997 (P =.005). Over the same period, rates of prophylactic maternal steroid therapy increased substantially and rates of RDS declined. Perinatal mortality rates among pregnancies reaching 34 weeks decreased from 12.9 per 1000 total births in 1988-1992 to 4.2 per 1000 total births in 1993-1997 (P =.05). CONCLUSION: Increases in preterm labor induction appear to be responsible for the recent increase in preterm birth among twins. These changes have been accompanied by decreases in perinatal morbidity and mortality among twin pregnancies that reach 34 weeks' gestation.

Adult↗
PubMed2001

Nodal vessels disease as a risk factor for atrial fibrillation after coronary artery bypass graft surgery.

OBJECTIVE: Atrial fibrillation (AF) is common after coronary artery bypass graft (CABG) surgery. Atrial ischaemia due to diseased atrioventricular (AV) and sinoatrial (SA) arteries has been proposed as a cause of AF post-CABG. We examined if the presence of diseased nodal arteries was a significant predictor of the development of AF post-CABG. METHODS: 100 consecutive cases (AF post-CABG) were compared to 100 consecutive controls (No AF post-CABG) with respect to pre-operative angiographic evidence of diseased nodal arteries. Cases and controls identified from the Society of Thoracic Surgeons database underwent detailed chart reviews to obtain data on potential risk factors. Patients were excluded if they were undergoing anything but a routine CABG procedure, were older than 65 years, or had previous AF. All angiograms were reviewed by a single radiologist blinded to outcome. The effect of grafting diseased nodal arteries on the development of AF post-CABG was also measured. A multiple logistic regression model was utilized to measure the effect of disease in each artery on the development of AF post-CABG. RESULTS: Cases and controls were comparable regarding potential risk factors, with the exception that the AF group was older than the non-AF group. Significant AV artery disease was detected in 78 cases compared to 74 controls (adjusted odds ratio (OR) OR=1.04, CI, 0.51-2.12, P=0.82). Significant SA artery disease was detected in 34 cases compared to 21 controls (adjusted OR=2.093, CI: 1.06-4.09, P=0.03). Six of ten patients having revascularization of their SA nodal artery developed AF versus 28 of 45 of those who did not (OR=0.91, CI: 0.18-5.06, P=0.58). Forty-eight of 87 patients having revasacularization of their AV nodal artery developed AF versus 30 of 65 of those who did not (OR=1.44, CI: 0.72-2.88, P=0.27). CONCLUSION: The presence of a diseased SA artery is significantly associated with AF post-CABG. Such association may be used to identify a subset of patients who might be targeted with prophylaxis.

Aged↗
PubMed2001

A preterm birth prevention project in Nova Scotia, Canada.

OBJECTIVE: The Halifax County Preterm Birth Prevention Project was designed to evaluate the effectiveness of a population-based preterm birth (PTB) prevention program in Nova Scotia from January 1995 through June 1997 (n = 10,326). METHODS: Preterm birth rates, adjusted for risk status and maternal age, were evaluated over time in Halifax County and compared to non-Halifax County parturients in Nova Scotia. Physician participation was evaluated by means of a mailed survey. RESULTS: There was no appreciable change in the overall (<37 weeks) or early (<34 weeks) PTB rates within or outside Halifax County during the intervention period compared to the preintervention period. Although not significant, the very (<30 weeks) PTB rate in Halifax County decreased by 40% from 0.53 to 0.32%, while outside Halifax County it remained stable (0.43-0.42%). There was a statistically significant decrease in early and very PTB associated with spontaneous labour, as well as an apparent shift in the timing of delivery from very preterm to preterm (> or =30 weeks). Participation among responding physicians was greater for high-risk than low-risk women, but full compliance with project recommendations was low. CONCLUSION: The overall ineffectiveness of the Halifax County Preterm Birth Prevention Project may reflect the reluctance of practitioners to fully incorporate the recommended prevention strategies into their practice. However, such interventions may reduce the risk of spontaneous early preterm birth.

Feasibility Studies↗
PubMed2001

Relation between trihalomethane compounds and birth defects.

OBJECTIVES: To evaluate the risk of birth defects relative to exposure to specific trihalomethanes in public water supplies. METHODS: A retrospective cohort study was conducted based on data from a population based perinatal database in Nova Scotia, Canada and from the results of routine water monitoring tests. The cohort consisted of women who had a singleton birth in Nova Scotia between 1988 and 1995 and who lived in an area with a municipal water supply. The birth defects analyzed included neural tube defects, cardiovascular defects, cleft defects, and chromosomal abnormalities. Two of the four trihalomethane compounds occur in large enough concentrations to be analyzed (chloroform and bromodichloromethane (BDCM)). RESULTS: Exposure to BDCM at concentrations of 20 microg/l or over was associated with an increased risk of neural tube defects (adjusted relative risk (RR) 2.5, 95% confidence interval (95% CI) 1.2 to 5.1) whereas exposure to chloroform was not. Exposure to BDCM of 20 microg/l and over was associated with decreased risks of cardiovascular anomalies (RR 0.3, 95% CI 0.2 to 0.7). There was a suggestion of an increased risk of chromosomal abnormalities associated with exposure to chloroform, and no evidence of any association between either trihalomethane compound and cleft defects. CONCLUSIONS: In this cohort, differences were found in the RR associated with exposure to chloroform and BDCM for each of the congenital anomalies under study. These findings point to the importance of examining specific byproduct compounds relative to risk for these birth outcomes and in particular implicate BDCM and other correlated disinfection byproducts in the aetiology of neural tube defects.

Abnormalities, Drug-Induced↗
PubMed2001

Rates and risk factors for recurrence of gestational diabetes.

OBJECTIVE: To determine the recurrence rate of gestational diabetes (GDM) during a subsequent pregnancy among women who had GDM during an index pregnancy and to identify factors associated with the probability of recurrence RESEARCH DESIGN AND METHODS: A retrospective longitudinal study was performed in Nova Scotia, Canada, of women who were diagnosed as having GDM during a pregnancy between the years of 1980 and 1996 and who had at least one subsequent pregnancy during this time period. When only the index and first subsequent pregnancy were analyzed, the cohort included 651 women. The recurrence rate of GDM in the pregnancy after the pregnancy with the initial diagnosis of GDM was determined. Multivariate regression models were constructed to model the recurrence of GDM in a subsequent pregnancy as functions of potential predictors to estimate RRs and CIs. RESULTS: The rate of recurrence of GDM in the pregnancy subsequent to the index pregnancy was found to the 35.6% (95% CI = 31.9-39.3%). Multivariate regression models showed that infant birth weight in the index pregnancy and maternal prepregnancy weight before the subsequent pregnancy were predictive of recurrent GDM. CONCLUSIONS: In this large cohort of women, slightly more than one-third of the subjects had diabetes in a subsequent pregnancy, which is consistent with recurrence rates in other predominately white populations. Strategies to reduce the occurrence of neonatal macrosomia and maternal prepregnancy obesity may help lower the rate of recurrence of GDM.

Analysis of Variance↗
PubMed2000

Maternal complications with placenta previa.

The purpose of this study is to describe the maternal complications of placenta previa. A population-based retrospective cohort study including all women delivered in the province of Nova Scotia, Canada from 1988 to 1995 was performed. Patient information was obtained from the Nova Scotia Atlee Perinatal Database and maternal complications were described for all women undergoing cesarean delivery. Prognostic factors for the risk of hysterectomy in woman with placenta previa were analyzed by multiple logistic regression. During the 8-year period, 308 cases of placenta previa were identified in 93,996 deliveries (0.33%). Maternal complications included hysterectomy [relative risk (RR) = 33.26], antepartum bleeding (RR = 9.81), intrapartum (RR = 2.48), and postpartum (RR = 1.86) hemorrhages, as well as blood transfusion (RR = 10.05), septicemia (RR = 5.55), and thrombophlebitis (RR = 4.85). Risk factors for need of hysterectomy in women with placenta previa include the presence of placenta accreta and previous cesarean delivery.

Adult↗
PubMed2000

Relation between stillbirth and specific chlorination by-products in public water supplies.

During water treatment, chlorine reacts with naturally occurring organic matter in surface water to produce a number of by-products. Of the by-products formed, trihalomethanes (THMs) are among the highest in concentration. We conducted a retrospective cohort study to evaluate the relationship between the level of total THM and specific THMs in public water supplies and risk for stillbirth. The cohort was assembled from a population-based perinatal database in the Canadian province of Nova Scotia and consisted of almost 50,000 singleton deliveries between 1988 and 1995. Individual exposures were assigned by linking mother's residence at the time of delivery to the levels of specific THMs monitored in public water supplies. Analysis was conducted for all stillbirths and for cause-of-death categories based on the physiologic process responsible for the fetal death. Total THMs and the specific THMs were each associated with increased stillbirth risk. The strongest association was observed for bromodichloromethane exposure, where risk doubled for those exposed to a level of [greater and equal to] 20 microg/L compared to those exposed to a level < 5 microg/L (relative risk = 1. 98, 95% confidence interval, 1.23-3.49). Relative risk estimates associated with THM exposures were larger for asphyxia-related deaths than for unexplained deaths or for stillbirths overall. These findings suggest a need to consider specific chlorination by-products in relation to stillbirth risk, in particular bromodichloromethane and other by-product correlates. The finding of a stronger effect for asphyxia deaths requires confirmation and research into possible mechanisms.

Adult↗
PubMed1999

Risk scoring, fetal fibronectin, and bacterial vaginosis to predict preterm delivery.

OBJECTIVE: To determine the value of markers for predicting spontaneous preterm birth. METHODS: One hundred forty asymptomatic gravidas were recruited from 20-24 weeks' gestation. Risk score was assessed, vaginal swabs were analyzed for bacterial vaginosis, and cervical and vaginal swab were tested for fetal fibronectin FDC-6, X18A4, and CAF. Univariate analysis was used to determine potential predictors (and combinations of predictors) of outcome. Multiple logistic regression was done to identify independent predictors of spontaneous preterm birth. Sensitivity, specificity, positive and negative predictive values; and odds and likelihood ratios were calculated for significant predictors. RESULTS: Predictors significantly associated with the primary outcome were preterm birth-risk score and vaginal fetal fibronection FDC-6 (logistic regression odds ratio [OR] 16.9 [95% confidence interval (CI) 3.1, 92.8]) and 8.0 ([95% CI 1.6, 38.2], respectively). Bacterial vaginosis, fetal fibronectin X18A4, fibronectin CAF, and cervical fetal fibronectin FDC-6 were not associated with spontaneous preterm birth; however, the statistical power to assess these variables was limited. The combination of positive preterm birth-risk score and vaginal fetal fibronectin FDC-6 had a sensitivity of 44.4%, specificity of 97.7%, positive predictive value of 57.1%, negative predictive value of 96.2%, and a significant likelihood ratio for a positive test of 19.4 (95% CI 5.1, 73.8). CONCLUSION: The combination of preterm birth-risk score and vaginal fetal fibronectin FDC-6 predicted spontaneous preterm birth. Intervention trials are required to determine whether a combination of screening tests will reduce rates of spontaneous preterm birth.

Adult↗
PubMed1999

Neonatal outcomes with placenta previa.

OBJECTIVE: To identify neonatal complications associated with placenta previa. METHODS: This was a population-based, retrospective cohort study involving all singleton deliveries in Nova Scotia from 1988 to 1995. The study group consisted of all completed singleton pregnancies complicated by placenta previa; all other singleton pregnancies were considered controls. Patient information was collected from the Nova Scotia Atlee perinatal database. Neonatal complications were evaluated while controlling for potential confounders. The data were analyzed using chi2, Fisher exact test, and multiple logistic regression. RESULTS: Among 92,983 pregnancies delivered during the study period, 305 cases of placenta previa were identified (0.33%). After controlling for potential confounders, neonatal complications significantly associated with placenta previa included major congenital anomalies (odds ratio [OR] 2.48), respiratory distress syndrome (OR 4.94), and anemia (OR 2.65). The perinatal mortality rate associated with placenta previa was 2.30% (compared with 0.78% in controls) and was explained by gestational age at delivery, occurrence of congenital anomalies, and maternal age. Although there was a higher rate of preterm births in the placenta previa group (46.56% versus 7.27%), there was no difference in birth weights between groups after controlling for gestational age at delivery. CONCLUSION: Neonatal complications of placenta previa included preterm birth, congenital anomalies, respiratory distress syndrome, and anemia. There was no increased occurrence of fetal growth restriction.

Cohort Studies↗
PubMed1999

Trihalomethanes in public water supplies and adverse birth outcomes.

We conducted a retrospective cohort study to evaluate the relation between the level of total trihalomethanes in drinking water and adverse birth outcomes. The study population comprised women residing in an area with municipal surface water who had a singleton birth in Nova Scotia between January 1, 1988, and December 31, 1995, or a pregnancy termination for a major fetal anomaly. We found little association between trihalomethane level and the outcomes related to fetal weight or gestational age, but we found an elevated relative risk for stillbirths for average trihalomethane levels during pregnancy of 100 microg/liter or greater (adjusted relative risk = 1.66; 95% confidence interval = 1.09-2.52) relative to women exposed to trihalomethane levels of 0-49 microg/liter. We saw little evidence of an elevated prevalence or dose-response pattern for congenital anomalies, with the possible exception of chromosomal abnormalities (adjusted prevalence ratio = 1.38 and 95% confidence interval = 0.73-2.59 for women exposed to trihalomethane levels of 100 microg/liter or greater).

Abnormalities, Drug-Induced↗
PubMed1998

Perinatal outcomes in women with asthma during pregnancy.

OBJECTIVE: To determine whether adverse perinatal outcome is associated with asthma or asthma medication use during pregnancy. METHODS: A retrospective cohort study was conducted of women who resided in Halifax County, Nova Scotia, and delivered between 1991 and 1993. Asthmatic women were classified into three groups, according to medication usage: no medications, beta agonists only, and steroids with or without other asthma medications. Outcomes compared among asthmatic and nonasthmatic women included maternal complications (pregnancy-induced hypertension, cesarean delivery, gestational diabetes, preterm birth, and antepartum and postpartum hemorrhage) and neonatal outcomes (low birth weight, congenital malformations, hyperbilirubinemia, and respiratory distress syndrome). RESULTS: The cohort included 817 asthmatic women and 13,709 nonasthmatic women. Overall, the prevalence of pregnancies complicated by asthma increased from 4.8% in 1991 to 6.9% in 1993. Asthmatic women were at increased risk for antepartum and postpartum hemorrhage, independent of medication usage. Asthmatic women taking steroids were at increased risk for pregnancy-induced hypertension (odds ratio [OR] 1.7; 95% confidence interval [CI] 1.0, 2.9). The only significant difference in neonatal outcome between asthma medication groups and nonasthmatic women was of an increased risk of hyperbilirubinemia in infants of women taking steroids (OR 1.9; 95% CI 1.1, 3.4). CONCLUSION: Risk of antepartum and postpartum hemorrhage is increased in asthmatic women, independent of medication usage. The increased incidence of neonatal hyperbilirubinemia and the borderline increased risk of pregnancy-induced hypertension may be complications of steroid use or may be related to poorly controlled asthma.

Adult↗
PubMed1997

Is Canada's sex ratio in decline?

In this issue (see pages 37 to 41) Dr. Bruce B. Allan and associates report a small but statistically significant decrease--of about 0.2%--in the proportion of male live births in Canada over the period 1970-90. In this editorial, factors that have been reported in the literature to influence sex ratio are examined within a Canadian context. The authors suggest that although the reasons for the apparent decline in the sex ratio in Canada are unclear, the increasing use of ovulation induction may be a contributing factor. Data from the Nova Scotia Atlee Perinatal Database are discussed with a view to explaining the trend observed in Atlantic Canada, but no obvious explanation emerges. The authors argue that when the period of observation is extended no overall change in the sex ratio is apparent. This would suggest a tendency toward stabilization rather than decline.

Abortion, Spontaneous↗
PubMed1997

Risk of congenital anomalies in children of parents occupationally exposed to low level ionising radiation.

OBJECTIVES: To evaluate the risk of having a child with a congenital anomaly in relation to occupational exposure to low level ionising radiation in the pre-conception period. METHODS: A case-control study based on the Canadian congenital anomalies registry used record linkage techniques to identify congenital anomalies among male and female workers in Canada's largest electric company. Cases were defined as parents of a child with a congenital anomaly born between April 1979 and December 1986 who had a congenital anomaly diagnosed within the first year of life. Controls were an individually matched sample of parents of a liveborn child without an anomaly. Risk of congenital anomaly was assessed in relation to parental exposure to ionising radiation acquired through work within a nuclear generating station of an electric power company. Exposure was assessed according to employment, whether or not the worker was monitored for radiation exposure, and quantitative estimates of radiation dose. RESULTS: Employment within the electric power industry was not associated with an increased risk of congenital anomalies in the offspring of mothers or fathers. Risk estimates for workers monitored (those who are likely to be exposed to ionising radiation) were 1.75 (95% confidence interval (95% CI) 0.86 to 3.55) for mothers and 0.84 (95% CI 0.68 to 1.05) for fathers. Exposure for fathers before conception, defined cumulatively and for six months before conception, was not associated with increased risk of anomalies in their offspring. There were no significant increases in risk found between type of anomaly and any measure of exposure, although the statistical power in these groups was limited. The study had insufficient numbers to evaluate the effects of ionising radiation in mothers as only three mothers had recorded doses > 0 mSv. CONCLUSIONS: Overall, workers in a nuclear power industry, and specifically those exposed before conception to low levels of ionising radiation, do not appear to be at an increased risk of having a liveborn child with a congenital anomaly.

Canada↗
PubMed1995

Prevalence of smoking among pregnant women in Nova Scotia from 1988 to 1992.

OBJECTIVE: To determine the prevalence of smoking during pregnancy in Nova Scotia and to identify women at high risk of smoking during pregnancy. DESIGN: Population-based descriptive study. SETTING: All hospitals providing obstetric services in Nova Scotia. PATIENTS: All 60 754 women residing in Nova Scotia who had a baby in hospital between 1988 and 1992; smoking data were available for 57,750 (95.1%) of them. OUTCOME MEASURES: Proportion of women who smoked during pregnancy and the maternal smoking rates by age, marital status, parity, attendance at prenatal classes and residence. RESULTS: Overall, 32.4% of the women smoked at some point during their pregnancy. The rate was highest among the women less than 20 years of age (47.0%) and decreased with each increasing 5-year age interval. Overall, the unmarried women were 2.1 times as likely to smoke as the married women. The smoking rates were highest among the women who were para 3 or greater regardless of age (women less than 20 were excluded here, since very few had such a parity). Of the nulliparous women, those who attended prenatal classes were less likely to smoke during pregnancy than those who did not attend. There was no relation between urban or rural residence and smoking rates. The smoking rates decreased little between 1988 and 1992 and in fact increased among the women 35 and over and among those who were para 3 or greater. CONCLUSIONS: The smoking rates among pregnant women in Nova Scotia changed little between 1988 and 1992. Therefore, it seems that current strategies for smoking cessation have not been successful. Since prenatal classes are more likely to attract nonsmokers than smokers, other avenues for education and cessation are necessary.

Adult↗
PubMed1995

Early catheter removal: a prospective study of 100 consecutive patients undergoing transurethral resection of the prostate.

OBJECTIVE: To determine whether early catheter removal after transurethral resection of the prostate (TURP) leads to early hospital discharge with no increase in complications. PATIENTS AND METHODS: From October 1992 50 consecutive patients undergoing TURP in each of two hospitals were catheterized for < 24 h or > 36-48 h after the operation. Patients were followed up to assess the frequency and extent of post-operative complications. RESULTS: The two groups, which were standardized as far as possible, had a similar outcome whether the catheter was removed within 24 h or > 36 h after TURP. CONCLUSION: Brief catheter drainage after TURP is safe and allows an earlier discharge from hospital than the standard duration of catheterization.

Aged↗
PubMed1994

The ambulatory treatment unit. An innovative model.

Changes in the healthcare delivery system have created a competitive marketplace that demands new programs to contain healthcare costs while providing more efficiently for patients' healthcare needs. One major change is a trend toward outpatient ambulatory healthcare. Procedures once performed in the hospital currently are done routinely on an outpatient basis. Drug/alcohol treatment units, rehabilitation centers, and occupational health centers provide long-term care on an outpatient basis. Home healthcare programs provide nursing services for patients who are chronically ill and for those with special recovery needs after discharge; hospice programs provide nursing care for terminally ill patients. Although change can be unsettling, it also provides new opportunities for nursing to be creative and innovative in providing client services that meet present demands. This article presents one such innovation, the development of an ambulatory treatment unit.

Ambulatory Care↗
PubMed1993

Case-control study of congenital anomalies in children of cancer patients.

OBJECTIVES: To determine whether the offspring of cancer survivors are at an increased risk of congenital anomalies and whether cancer therapy before conception is associated with such an increase. DESIGN: Case-control study using computerised record linkage. SETTING: Ontario, Canada. SUBJECTS: Parents of children born during April 1979 to December 1986 who had a congenital anomaly diagnosed within the first year of life (45,200 mothers and 41,158 fathers) and a matched sample of parents whose children did not have a congenital anomaly (45,200 mothers and 41,158 fathers). MAIN OUTCOME MEASURES: Cancer diagnosed in either parent before conception and radiotherapy to the pelvis or abdomen or chemotherapy with an alkylating agent. RESULTS: Among the mothers, 54 cases and 52 controls were identified as having had cancer diagnosed in Ontario (relative risk = 1.04, 95% confidence interval 0.7 to 1.5) and among the fathers, 61 cases and 65 controls were identified (0.9, 0.7 to 1.4). No significant associations were found between congenital anomalies in the offspring and any type of cancer treatment in either the mothers or the fathers. CONCLUSIONS: The risk of congenital anomalies among liveborn offspring whose parents have had cancer or been treated for cancer is not higher than that in the general population.

Adult↗