To assess the accuracy of the calculated risk for trisomy 18 assigned to individual women screened with the second-trimester triple test.
The study was based on 382598 women screened in the Ontario Maternal Serum Screening Programme between October 1993 and September 2000. Of the women screened, 111 cases of trisomy 18 were identified. Originally, 92874 women were screened using a risk cut-off level method. Estimated risks of trisomy 18 were calculated by applying published population parameters for the remaining women screened using a fixed analyte cut-off method. Women were ranked according to their individual risk for trisomy 18 syndrome in decreasing order and divided into 12 groups. The mean calculated risks of having an affected pregnancy at term for each group were compared with the birth prevalence of the corresponding group after allowing for spontaneous fetal losses.
Agreement between the mean calculated risks and the observed prevalence was seen across the entire risk range, although women identified as having high-risk pregnancies had an actual prevalence that was somewhat lower than that estimated by the screen.
The calculated risk for trisomy 18 syndrome assigned to the individual woman on the basis of the risk cut-off method accurately reflects their risk of having a term trisomy 18 syndrome pregnancy.
To review the risk of in utero infection through amniocentesis in women with hepatitis B, hepatitis C, or human immunodeficiency virus (HIV).
Fetal and neonatal morbidity and mortality.
Review articles, meta-analyses, and MEDLINE searches from 1966 to 2002 for English-language articles related to amniocentesis, fetal and neonatal infection, and hepatitis B, hepatitis C, or HIV.
The evidence collected was reviewed by the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and quantified using the Evaluation of Evidence guidelines developed by the Canadian Task Force on the Periodic Health Exam.
1. The risk of fetal hepatitis B infection through amniocentesis is low. However, knowledge of the maternal hepatitis B e antigen status is valuable in the counselling of risks associated with amniocentesis. (II-1C) 2. Amniocentesis in women infected with hepatitis C does not appear to significantly increase the risk of vertical transmission, but women should be counselled that very few studies have properly addressed this possibility. (II-2C) 3. In HIV-positive women all noninvasive screening tools should be used prior to considering amniocentesis. (II-2D) 4. For women infected with hepatitis B, hepatitis C, or HIV, the addition of noninvasive methods of prenatal risk screening, such as nuchal translucency, triple screening, and anatomic ultrasound, may help in reducing the age-related risk to a level below the threshold for genetic amniocentesis. (II-2C) 5. For those women infected with hepatitis B, hepatitis C, or HIV who insist on amniocentesis, every effort should be made to avoid inserting the needle through the placenta. (II-1B) VALIDATION: These guidelines have been approved by the SOGC Genetics Committee, SOGC Executive, and SOGC Council.
The Society of Obstetricians and Gynaecologists of Canada.
Amniocentesis is a relatively safe and reliable procedure. However, there probably is a slightly increased risk of fetal loss following amniocentesis (approximately 0.5%). Other risks are minimal. Amniocentesis should be performed by obstetrician-gynecologists familiar with both the indications for the technique of second-trimester genetic amniocentesis. Recent social trends, including the increased availability of medical information to the lay public and the interest of many women in delaying childbearing, will increase public demand for antenatal diagnosis. It is important that obstetrician-gynecologists prepare to meet these demands.
High amniotic fluid erythropoietin concentration reflects chronic fetal hypoxia. Our aim was to study amniotic fluid erythropoietin concentration in relation to neonatal outcome in pregnancies complicated by intrauterine growth restriction.
Retrospective case series.
Helsinki University Hospital, Finland.
A total of 66 singleton pregnancies complicated by intrauterine growth restriction.
Amniocentesis or amniotic fluid sampling at cesarean section was performed between 24 and 34 gestational weeks. Values of amniotic fluid erythropoietin were quantitated with immunochemiluminometric assay. Normal amniotic fluid erythropoietin was defined as 27 IU/L.
Adverse neonatal outcome.
Abnormal biophysical profile and reversed end-diastolic flow in umbilical artery were associated with abnormal amniotic fluid erythropoietin (p
Congenital adrenal hyperplasia (CAH) due to deficiency of the enzyme 21-hydroxylase (21-OH) is distinguished in classical (C-CAH) and non-classical form (NC-CAH), and it is also one of the most common autosomal recessive inherited disorders in humans. The prevalence of C-CAH is between 1:10,000 and 1:15,000 among the live neonates of North America and Europe while the NC-CAH occurs in approximately 0.2% of the general white population. The highest incidence of CAH (1:282 and 1:2141, respectively) has been evaluated in Yupik Eskimos in Alaska and in the populations of the island La Reunion (France), while the lower was detected in New Zealand newborns (0.3%). Nowadays, it has been established that except for the adrenal cortex in CAH cases, the adrenal medulla was also affected. In human 21-OH deficient adrenal gland it has been discovered that not only the chromaffin cells formed extensive neurites, expanding between adrenocortical cells, but also that the adrenal androgens promote outgrowth, whereas glucocorticoids preserve neuroendocrine cells. It seems that normal cortisol secretion by the adrenal cortex is necessary for adrenomedullary organogenesis. The synthesis of 21-OH is controlled by the active CYP21A2 gene located at a distance of 30 kb from a highly homologous pseudogene designated CYP21A1P.
Informed choice is often lacking in women's decisions about prenatal screening.
The aim of this study is to evaluate how well midwives in Ontario, Canada are facilitating informed choice in this area.
An Internet-based survey was used to investigate 171 midwifery clients' knowledge, attitude towards and experience of prenatal genetic screening tests, and to determine the proportion of study participants who made an informed choice about prenatal screening.
All participants demonstrated adequate knowledge of prenatal screening. The vast majority (93.0%) of participants made an informed choice. Participants who chose to screen had lower knowledge scores than those who opted out of screening. Client satisfaction rates in regard to care received in this area ranged from 97% to 100%.
Results of this study suggest that Ontario midwives are effective in conveying information on prenatal genetic screening, contributing to high levels of client knowledge and satisfaction in comparison to similar studies in other jurisdictions.
Customized birth weight percentiles are weight-for-gestational-age percentiles that account for the influence of maternal characteristics on fetal growth. Although intuitively appealing, the incremental value they provide in the identification of intrauterine growth restriction (IUGR) over conventional birth weight percentiles is controversial. The objective of this study was to assess the value of customized birth weight percentiles in a simulated cohort of 100,000 infants aged 37 weeks whose IUGR status was known. A cohort of infants with a range of healthy birth weights was first simulated on the basis of the distributions of maternal/fetal characteristics observed in births at the Royal Victoria Hospital in Montreal, Canada, between 2000 and 2006. The occurrence of IUGR was re-created by reducing the observed birth weights of a small percentage of these infants. The value of customized percentiles was assessed by calculating true and false positive rates. Customizing birth weight percentiles for maternal characteristics added very little information to the identification of IUGR beyond that obtained from conventional weight-for-gestational-age percentiles (true positive rates of 61.8% and 61.1%, respectively, and false positive rates of 7.9% and 8.5%, respectively). For the process of customization to be worthwhile, maternal characteristics in the customization model were shown through simulation to require an unrealistically strong association with birth weight.
OBJECTIVES: To assess whether lactate determination in vaginal fluid is associated with, and can predict, onset of labour for women with suspected prelabour rupture of the membranes (PROM). DESIGN: Prospective observational study. SETTING: Labour ward at Soder Hospital, Stockholm, Sweden. POPULATION: Women with suspected PROM after 34 weeks of gestation, who later had spontaneous onset of labour (n = 179). METHODS: All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour. MAIN OUTCOME MEASURES: Time from examination to onset of labour (cervix > or =4 cm), within 24 hours and 48 hours. RESULTS: The median time interval between examination and spontaneous onset of labour was 8.4 hours for women with 'high' lactate (> or =4.5 mmol/l) and 54 hours for those with 'low' lactate concentrations ( or =4.5 mmol/l) in vaginal fluid can be used to predict whether a woman with suspected PROM will commence spontaneous onset of labour within 24 or 48 hours.
The aim of the study was to describe the opinion of pregnant women who had accepted or declined an alpha-fetoprotein test (AFP) not only on AFP-screening in general, but also on whether every pregnant woman should be offered amniocentesis (AC)/chorion villus sampling (CVS) and an ultrasound scan for fetal malformations. An additional aim was to describe pregnant women's attitudes concerning continued research in the prenatal field. The study was performed as a questionnaire study in two regions over a one-year period from October 1, 1988 to September 30, 1989. Results are based on answers from 3331 women who had taken an AFP-test and 336 women who had declined the offer of a test. A total of 79% of the women thought that an AFP-test, 70% that an ultrasound scan for fetal malformations and 26% that AC or CVS should be offered to all pregnant women. Fifty-nine percent of the women were positive towards continued research in the prenatal field. Women who had had an AFP-test were generally much more positive towards screening and research than women who had declined, who were generally against. Women who had left school without a high school degree were on average more positive towards the screening issues than women who had this degree. In conclusion, the results obtained in this study strongly suggest that women's attitudes are very dependent on how the prenatal screening programme is already organized in their local area.