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Biomedical subjects

Jane Halliday

Publications and source records attributed to Jane Halliday.

17 recordsLinked to original sources
PubMed2006

Outcomes of IVF conceptions: are they different?

Perinatal outcomes, such as preterm delivery, low birth weight and some obstetric complications, are increased significantly after in-vitro fertilization (IVF) compared with spontaneously conceived pregnancies. The degree of difference is greater for singletons than for twins, especially with regard to preterm delivery which is increased two fold in IVF singletons and by 40% in twins. It is difficult to obtain accurate outcome information because of unmeasured confounders such as smoking status and fetal reduction. It is also unknown whether IVF technologies or patient infertility is the major contributor to adverse outcomes. Birth defects are increased, shown in a number of systematic reviews, and there has been a particular interest in imprinting syndromes. Epigenetic modifications may play a larger role in IVF outcomes, as yet unidentified. There is no apparent increase in adverse outcomes in children up to adolescence, although further studies are needed to examine longer-term risks, including those for cancer.

Abnormalities, Multiple↗
PubMed2006

Evaluation of a decision aid for prenatal testing of fetal abnormalities: a cluster randomised trial [ISRCTN22532458].

BACKGROUND: By providing information on the relative merits and potential harms of the options available and a framework to clarify preferences, decision aids can improve knowledge and realistic expectations and decrease decisional conflict in individuals facing decisions between alternative forms of action. Decision-making about prenatal testing for fetal abnormalities is often confusing and difficult for women and the effectiveness of decision aids in this field has not been established. This study aims to test whether a decision aid for prenatal testing of fetal abnormalities, when compared to a pamphlet, improves women's informed decision-making and decreases decisional conflict. METHODS/DESIGN: A cluster designed randomised controlled trial is being conducted in Victoria, Australia. Fifty General Practitioners (GPs) have been randomised to one of two arms: providing women with either a decision aid or a pamphlet. The two primary outcomes will be measured by comparing the difference in percentages of women identified as making an informed choice and the difference in mean decisional conflict scores between the two groups. Data will be collected from women using questionnaires at 14 weeks and 24 weeks gestation. The sample size of 159 women in both arms of the trial has been calculated to detect a difference of 18% (50 to 68%) in informed choice between the two groups. The required numbers have been adjusted to accommodate the cluster design, miscarriage and participant lost--to--follow up. Baseline characteristics of women will be summarised for both arms of the trial. Similarly, characteristics of GPs will be compared between arms. Differences in the primary outcomes will be analysed using 'intention-to-treat' principles. Appropriate regression techniques will adjust for the effects of clustering and include covariates to adjust for the stratifying variable and major potential confounding factors. DISCUSSION: The findings from this trial will make a significant contribution to improving women's experience of prenatal testing and will have application to a variety of maternity care settings. The evaluation of a tailored decision aid will also have implications for pregnancy care providers by identifying whether or not such a resource will support their role in providing prenatal testing information.

Cluster Analysis↗
PubMed2006

Trends of selected malformations in relation to folic acid recommendations and fortification: an international assessment.

BACKGROUND: Two crucial issues relative to the benefits and impact of folic acid in the prevention of birth defects are whether supplementation recommendations alone, without fortification, are effective in reducing the population-wide rates of neural tube defects (NTDs), and whether such policies can reduce the occurrence of other birth defects. Using data from 15 registries, we assessed rates and trends of 14 major defects, including NTDs, in areas with official recommendations or fortification to assess the effectiveness of recommendations and fortification on a wide range of major birth defects. METHODS: We evaluated surveillance data through 2003 on major birth defects from population-based registries from Europe, North America, and Australia. All included ascertainment of pregnancy terminations (where legal). Trends before and after policies or fortification were assessed via Poisson regression and were compared via rate ratios. RESULTS: Significant changes in trends were seen for NTDs in areas with fortification but not in areas with supplementation recommendations alone. For other major birth defects, there was an overall lack of major trend changes after recommendations or fortification. However, some significant declines were observed for select birth defects in individual areas. CONCLUSIONS: Recommendations alone remain an ineffective approach in translating the known protective effect of folic acid in population-wide decline in NTD rates. Fortification appears to be effective in reducing NTDs. The effect on other birth defects remains unclear.

Dietary Supplements↗
PubMed2006

Health and developmental outcome of children following prenatal diagnosis of confined placental mosaicism.

OBJECTIVE: To determine the long-term health and development of a cohort of children in whom confined placental mosaicism (CPM) was diagnosed at prenatal diagnosis. METHODS: A retrospective cohort study was performed comparing 36 children in whom CPM had been diagnosed prenatally with 195 controls subjects in whom a normal karyotype had been detected prenatally. Data comprising birth information, health, health service utilisation, growth, development, behaviour, and the family were collected by a maternal questionnaire administered when the subjects were aged between 4 and 11 years. RESULTS: CPM cases did not differ from controls across a broad range of health measures and there were no major health problems or birth defects among the CPM group. No increase was detected in the incidence of intrauterine growth retardation (IUGR) among CPM cases; however, postnatal growth was reduced compared with controls (p = 0.047). Development and behaviour in CPM cases was similar to that of controls. CONCLUSIONS: The prenatal diagnosis of CPM is not associated with an increased risk of birth defects or developmental problems, but may be associated with decreased growth.

Child↗
PubMed2006

Factor V Leiden mutation: a contributory factor for cerebral palsy?

Fifty-seven children with cerebral palsy (CP) and imaging evidence of vascular thrombosis (study group) and 167 children with CP and other imaging finds (control group)were selected. Sixty-one per cent of the study group were male and 53 (93%) had spastic hemiplegia compared with the control group, of whom 55% were male and 54 (32%) had a diagnosis of spastic hemiplegia. Mean age was 5 years 11 months (SD 5y 1mo) for the study group and 7 years 7 months (SD 4y 7mo) for the control group. Blood spots on Guthrie cards or buccal swabs were used to test both groups and their mothers for the factor V Leiden (fVL) mutation, which predisposes carriers to thrombophilia. Mothers were interviewed to gather antenatal, perinatal, demographic, and socio-economic data. The frequency of the fVL mutation in children with evidence of vascular thrombosis and their mothers was not statistically different from the frequency in children with CP with other imaging findings and their mothers. The frequency of the fVL mutation was significantly higher than the expected population frequency of 4% in the study group (10.5%, p=0.012) and in mothers of the control group (7.2%, p=0.036).

Birth Weight↗
PubMed2005

Screening and preventive behaviors one year after predictive genetic testing for hereditary nonpolyposis colorectal carcinoma.

BACKGROUND: Prevention benefits from predictive genetic testing for cancer will only be fully realized if appropriate screening is adopted after testing. The current study assessed screening and preventive behaviors during 12 months after predictive genetic testing for hereditary nonpolyposis colorectal carcinoma (HNPCC) in an Australian clinical cohort. METHODS: Participants received predictive genetic testing for HNPCC at one of five Australian familial cancer clinics. Data on self-reported screening behaviors (colonoscopy, and endometrial sampling and transvaginal ultrasound for women) and prophylactic surgery (colectomy, and hysterectomy and bilateral oophorectomy for women) were collected using postal questionnaires before (baseline) and 12 months after receipt of genetic test results. Age, gender, perceived risk of cancer, and cancer-specific distress were assessed as predictors of colonoscopic screening. RESULTS: In the current study, 114 participants returned baseline questionnaires (32 carriers and 82 noncarriers of an HNPCC mutation). Ninety-eight participants also returned a 12-month follow-up questionnaire. Of those > or = 25 years, 73% reported having had a colonoscopy before genetic testing. At follow-up, 71% (15 of 25) of carriers and 12% (8 of 65) of noncarriers reported having a colonoscopy in the 12 months after receipt of test results. The reduction in colonoscopy among noncarriers was statistically significant (P < 0.001). High perceived risk was associated with colonoscopy at baseline. At follow-up, mutation status was the only variable significantly associated with colonoscopy. Among female mutation carriers, 47% reported having transvaginal ultrasonography and 53% endometrial sampling during follow-up. There was low uptake of prophylactic surgery for colorectal, endometrial, or ovarian carcinomas. CONCLUSIONS: The majority of individuals reported appropriate screening behaviors after predictive genetic testing for HNPCC. The small group of noncarriers who had screening after genetic testing might benefit from additional counseling.

Adult↗
PubMed2005

Facilitating family communication about predictive genetic testing: probands' perceptions.

The responsibility of informing relatives that predictive genetic testing is available often falls to the proband. Support is required during this process, however the perceived utility of genetic counseling and other strategies to facilitate communication have not been explored. We investigated the experiences of 12 individuals with hereditary nonpolyposis colorectal cancer (HNPCC) in a semistructured telephone interview. Respondents informed their immediate family about the availability of genetic testing, however many more-distant relatives were not directly informed. Respondents were mostly satisfied with the way they told family members about testing and had mixed views about the usefulness of genetic counseling. Gender differences were observed, with most men expressing a need for guidance or support in communicating to relatives. Letters and booklets were thought to enhance the quality of information but the provision of further aids is unlikely to increase the number of relatives made aware of predictive testing by the proband.

Adult↗
PubMed2005

Genetic professionals' reports of nondisclosure of genetic risk information within families.

Patients attending genetic clinics are often the main gatekeepers of information for other family members. There has been much debate about the circumstances under which professionals may have an obligation, or may be permitted, to pass on personal genetic information about their clients but without their consent to other family members. We report findings from the first prospective study investigating the frequency with which genetics professionals become concerned about the failure of clients to pass on such information to their relatives. In all, 12 UK and two Australian regional genetic services reported such cases over 12 months, including details of actions taken by professionals in response to the clients' failure to disclose information. A total of 65 cases of non-disclosure were reported, representing <1% of the genetic clinic consultations in the collaborating centres during the study period. These included 39 cases of the failure of parents not passing full information to their adult offspring, 22 cases where siblings or other relatives were not given information and four cases where information was withheld from partners -- including former and prospective partners. Professionals reported clients' reasons for withholding information as complex, more often citing concern and the desire to shield relatives from distress rather than poor family relationships. In most cases, the professionals took further steps to persuade their clients to make a disclosure but in no instance did the professional force a disclosure without the client's consent.

Attitude of Health Personnel↗
PubMed2005

Influence of prenatal diagnosis and pregnancy termination of fetuses with birth defects on the perinatal mortality rate in Victoria, Australia.

Historical data show that in Victoria birth defects have accounted for approximately 25% of all perinatal deaths. Terminations of pregnancies (TOPs) for birth defects occurring at > or =20 weeks gestation are included in the population-based perinatal data collection. These are classified as stillbirths or neonatal deaths. Some would have survived the perinatal period if no termination had taken place, and as a result they have the effect of increasing the perinatal mortality rate (PMR). Conversely, TOPs <20 weeks gestation, of fetuses with lethal birth defects that would have resulted in a perinatal death, are not included in the statistics and therefore reduce the PMR. The aim of this study was to examine the effect on the PMR of TOPs following the prenatal detection of birth defects, taking into account the severity or 'lethality' of the birth defects. Data on live births, stillbirths, neonatal deaths and TOPs carried out because of a birth defect were collected from the Victorian Birth Defects Register (BDR) for 1989-2000. Birth defects were categorised into three groups, according to the estimated likelihood of a baby with that condition dying in the perinatal period: a 'lethal' birth defect was one where there was >50% likelihood of death, 'possibly lethal' 15-50% and 'non-lethal' less than 15%. Based on these 'lethality' groups and associated assumptions about average survival rates beyond the neonatal period, the PMR was recalculated. TOPs for 'non-lethal' birth defects at > or =20 weeks gestation increased the PMR by 3.8%. TOPs for 'lethal' birth defects <20 weeks decreased the PMR by 14.4%. The net effect on the overall PMR from TOPs for birth defects was a 10.6% decrease.

Abortion, Induced↗
PubMed2004

An epidemiologic study of isolated cleft lip, palate, or both in Victoria, Australia from 1983 to 2000.

OBJECTIVES: To report the epidemiological characteristics of isolated cleft lip, cleft palate or both (CL +/- P and CP) using population-based data in Victoria, Australia. DESIGN: Descriptive study of a cohort of children born between 1983 and 2000 notified to the Victorian Birth Defects Register by multiple ascertainment sources. PARTICIPANTS: Data were collected on patients identified with CL +/- P and CP without associated defects classified as live births, stillbirths, neonatal deaths, and terminated pregnancies < 20 weeks' gestation following prenatal identification. Information was collected on sex, plurality, maternal age, and country of birth. RESULTS: The overall prevalence (per 10,000 pregnancies) of CL +/- P was 7.8 (95% confidence interval [CI] = 7.30, 8.33; cleft lip [CL] 3.3; 95% CI = 2.97, 3.65, CL+P 4.5; 95% CI = 4.13, 4.91) and cleft palate (CP), 4.3 (95% CI = 3.89, 4.66). The prevalence of CL + P was higher among stillbirths, neonatal deaths, and terminated pregnancies than CL (without CP) and CP. Boys were at greater risk than girls for CL +/- P and girls at greater risk than boys for CP. Regardless of cleft type, there was a nonsignificant excess of clefts among singleton births than multiple births and no related effects of maternal age or country of birth. CONCLUSIONS: The prevalence of isolated CL +/- P and CP in Victoria parallels other population-based studies of the same conditions. Inclusion of stillbirths, neonatal deaths, and terminations had little impact on rates. The effect of sex and plurality on cleft type is consistent with the literature, but the effects of maternal age and country of birth remain equivocal. Further studies focusing on certain ethnic groups are warranted to explain the higher rates observed.

Analysis of Variance↗
PubMed2003

Minimum birth prevalence of mitochondrial respiratory chain disorders in children.

Mitochondrial respiratory chain disorders comprise a group of perhaps several hundred different genetic diseases. Each individual disorder is rare, but collectively they account for substantial use of health care resources. However, few accurate data on prevalence are available due to problems such as variation in clinical presentation, age of onset, referral practices and limitations of diagnostic methodologies. With this retrospective study, we aimed to determine the minimum birth prevalence of respiratory chain disorders that have onset in childhood, that is the proportion of births that will have onset of symptoms caused by a respiratory chain defect by 16 years of age. Of the 1 706 694 children born in the three south-eastern states of Australia (New South Wales, Victoria and South Australia) between January 1st 1987 and December 31st 1996, samples from 430 were referred for investigation of a respiratory chain disorder. Definite diagnosis of a respiratory chain disorder was made in 86 cases based on defined clinical, pathological, enzyme and molecular criteria. Age at presentation ranged from 0 to 129 months (median 4 months). The total data set predicts a minimum birth prevalence for respiratory chain disorders in children of 5.0/100 000 [95% confidence interval (CI) 4.0-6.2]. A significantly higher figure of 58.6/100 000 (95% CI 34.7-92.6) was noted for Australian families of Lebanese origin. Clinical awareness of respiratory chain disorders and investigation methods have improved since 1987, but not all affected children would have been recognized as such from the more recent years. The minimum birth prevalence of 6.2/100 000 (95% CI 4.5-8.4) for the 43 patients born between 1991 and 1994 is thought to be a more accurate estimate for respiratory chain disorders presenting in childhood. Combining our data with a previous study on prevalence of adult-onset respiratory chain disorders predicts a minimum birth prevalence of 13.1/100 000 or 1/7634 for respiratory chain disorders with onset at any age.

Age of Onset↗
PubMed2002

Predictive genetic testing: high risk expectations in the face of low risk information.

The aims of this cross-sectional, questionnaire study were (1) to estimate the proportion of those receiving negative ("low risk") results following predictive genetic testing who expect to undergo clinically unnecessary future screening and (2) to examine the factors associated with this expectation. Of 127 adults receiving negative results following predictive genetic testing for familial adenomatous polyposis (FAP), 54 people (42%) were expected to attend for future bowel screening. The main predictor was doubt about the accuracy of genetic test results. Expecting to attend was also associated univariately with perceiving the chance of developing FAP as higher, being more worried about this, perceiving the test result to be more uncertain and threatening, and holding a behavioral model of the cause of FAP. Attendance for health screening may be influenced by people's perception of the accuracy of genetic tests that they have undergone. Future research should investigate test presentation and influences on test perception.

Adult↗
PubMed2002

Likelihood of attending bowel screening after a negative genetic test result: the possible influence of health professionals.

This study was undertaken to determine the extent to which the reported likelihood of attending future bowel screening following negative genetic testing results for familial adenomatous polyposis (FAP) varies between the type of health professional providing care and the country of testing. The study subjects were 103 unaffected adults at risk for FAP who received negative results following predictive DNA testing. Our study indicates that the reported likelihood of attending bowel screening was higher in those given results by nongenetics physicians, rather than by genetics professionals; the reported likelihood of attending bowel screening under these circumstances was also higher in the UK than in Australia. Both of these results were affected by the perceived chances of developing FAP, and, in the case of the country of testing, by the perceived accuracy of the genetic test result and the perceived seriousness of the disease. How and what health professionals communicate with patients about genetic testing may explain the differences between type of health professional and country of testing and attitudes toward bowel screening. If this is the case, training in communication may change patients' perceptions and, in turn, their behavioral intentions and actions following a negative test result.

Adenomatous Polyposis Coli↗