Biomedical subjects

Boaz Weisz

Publications and source records attributed to Boaz Weisz.

At least 19 recordsLinked to original sources

PubMed2007

Fetal cardiomyopathy--in utero evaluation and clinical significance.

OBJECTIVE: To describe the prenatal diagnosis and outcome of fetal cardiomyopathy (CM). METHODS: The charts, photographs and videotapes of all fetuses with CM, who were assessed during pregnancy at two referral centers, were reviewed. RESULTS: The diagnosis of CM was established in 12 fetuses. All had structurally normal hearts, and all cases were diagnosed after 23 weeks of gestation, following normal early fetal echocardiogram. Three clusters of fetal CM appeared: Familial--two sib fetuses of a mother, who is a second generation of CM. Both had dilated CM and pathological findings were consistent with the diagnosis of endocardial fibroelastosis. Secondary--CM that was induced by another factor. Idiopathic--six cases of CM without an underlying specific etiology. Three women elected to terminate their pregnancy. Among the nine who delivered, four had a favorable outcome with normal cardiac function at the age of 1 month, in which three belonged to the secondary category, and five cases were complicated by fetal/infant death. CONCLUSIONS: CM may develop during fetal life and might be diagnosed by prenatal echocardiography. Normal cardiac findings in a midtrimester fetus do not exclude subsequent development of CM. Detailed prenatal sonographic examination may aid in determining the neonatal outcome.

Adult↗

PubMed2006

An update on antenatal screening for Down's syndrome and specific implications for assisted reproduction pregnancies.

Since the introduction of antenatal serum screening for Down's syndrome (DS) more than two decades ago, several screening approaches have been utilized in routine clinical practice. The current DS screening strategies involve mid-trimester serum biochemistry tests, first trimester tests combining sonographic markers and serum biochemistry and integration of first and second trimester markers. In this review, we evaluate the performance of DS screening strategies according to the Serum, Urine and Ultrasound Screening Study (SURUSS), the First and Second Trimester Evaluation of Risks (FASTER) Trial and the Serum Biochemistry and Fetal Nuchal Translucency Screening (BUN) Study. We also evaluate the performance of first trimester screening in studies and meta-analyses by other groups. Specific issues related to assisted reproduction technology (ART) pregnancies are also addressed in this review.

Biomarkers↗

PubMed2006

Antenatal noninvasive treatment of patients at risk for alloimmune thrombocytopenia without a history of intracranial hemorrhage.

OBJECTIVE: The purpose of this study was to evaluate noninvasive management of alloimmune thrombocytopenia that included only the blind administration of immunoglobulin. STUDY DESIGN: Seventeen women with 30 pregnancies that were at risk of neonatal alloimmune thrombocytopenia were included. Except for 6 cases, in which the women refused treatment, 24 pregnancies were managed by the weekly administration of intravenous immunoglobulin without monitoring platelet count. RESULTS: The mean platelet count at birth after intravenous immunoglobulin treatment was 118,000/microL, compared with 25,000/microL among the 17 first affected infants and 24,000/microL among the 6 infants whose mothers refused treatment (P < .05). Only 8% of the treated fetuses had platelet counts of <30,000/microL at birth, compared with 70% of the untreated infants (P < .05). None of the treated and nontreated fetuses had an intracranial hemorrhage. CONCLUSION: Noninvasive management of alloimmune thrombocytopenia that consists of only immunoglobulin administration is highly effective and seems safe in women without a history of fetal/neonatal intracranial hemorrhage.

Adult↗

PubMed2006

Longitudinal assessment of insulin sensitivity in pregnancy. Validation of the homeostasis model assessment.

OBJECTIVE: To validate the use of the homeostasis model assessment (HOMA) for measurement of insulin sensitivity in obese women during gestation and the postpartum period. DESIGN: Three consecutive measurements of insulin resistance (IR) were performed during and after pregnancy to compare the homeostasis model assessment insulin sensitivity index (HOMA-IR) to glucose utilization rates obtained during hyperinsulinaemic euglycaemic clamps (G(Rd)). PATIENTS: Six obese women (mean second trimester BMI = 30.4 kg/m(2)) with normal glucose tolerance were studied during the second and third trimesters of pregnancy and once in the postpartum period. Thus, there were a total of 18 measurements for analysis. RESULTS: Correlations between the rate of glucose disappearance (G(Rd)) (the gold standard) and the HOMA-derived metabolic parameters of insulin sensitivity were significant, with a multiple R(2) of 43.5% (P = 0.003). However, when controlling for variations between patients using dummy variables, we observed that one patient differed from the other five in the relationship between G(Rd) and HOMA-IR. Applying this regression we obtained a R(2) of 72.6% (P < 0.001). When the regression constant was omitted, we observed that the individual trends during pregnancy and postpartum in two patients differed statistically from the other patients between the two assessments, and we obtained a multiple R(2) of 97.3% (< 0.001). CONCLUSIONS: HOMA estimation of insulin resistance is appropriate for use during both the second and third trimesters of pregnancy and postpartum in obese women with normal glucose tolerance. It lacks sensitivity for the evaluation of individuals, where more precise measures of insulin sensitivity should be utilized.

Adult↗

PubMed2006

Hypothesis: the placental 'steal' phenomenon - a possible hazard of amnioreduction.

The twin-twin transfusion syndrome (TTTS) complicates approximately 15% of monochorionic twin pregnancies. Severe TTTS is associated with poor neonatal outcome and a relatively high rate of neurological abnormalities. Some studies have suggested this outcome to be more severe in cases treated by amnioreduction. In this paper we present a hypothesis that radical amnioreduction performed after 24 weeks of gestation might cause a shift of blood from the fetus into the placenta. This could explain some of the severe neurological outcomes, such as hypoxic ischemic brain damage, seen in these cases.

Amniotic Fluid↗

PubMed2005

Scanning for chorionicity: comparison between sonographers and perinatologists.

OBJECTIVE: In most prenatal settings, twin pregnancies are initially evaluated by sonographers. Pregnancies diagnosed as monochorionic are subsequently referred to perinatologists or specialists in fetal medicine for the confirmation of chorionicity. In order to assess this screening strategy, we have compared the diagnosis of chorionicity made by the sonographers in the ultrasound department with the diagnosis done in the fetal medicine unit. METHODS: A cohort of women presenting with twin pregnancy and booked for prenatal care at University College London Hospitals over a 4-year period were investigated prospectively. All women were scanned at their initial visit at 11-14 weeks in the ultrasound department (US), and were subsequently referred to the Fetal Medicine Unit (FMU) for a second ultrasound evaluation. Ultrasound data were compared and diagnosis of chorionicity was confirmed by examination of the inter-twin membranes after delivery. RESULTS: Chorionicity was determined in 172 twin cases by the two different departments. The overall rate of concordant chorionicity determination between both units was 90.1%. The rate of discordant results in dichorionic pregnancies was extremely small, 1 in 119 pregnancies (0.8%). The rate of discordant results for monochorionic diamniotic pregnancies was 5.5%. Monoamniotic pregnancies were over-diagnosed by the US technicians. DISCUSSION: These results demonstrate that DC/DA chorionicity is accurately determined by sonographers at less than 14 weeks. In our opinion, it is both efficient and safe to rely on the diagnosis of the sonographers in DC/DA pregnancies in early pregnancy. In such pregnancies, a decision can be made either not to refer these patients for further evaluation of chorionicity by the fetal medicine team or to postpone the referral to after 14 weeks.

Chorion↗

PubMed2005

Invasive diagnostic procedures in twin pregnancies.

The rising rate of multiple pregnancies and its association with advanced maternal age has expanded the need for prenatal diagnosis in twins and higher order gestations. The complexity of the invasive diagnostic procedures and the risk of loss of an unaffected twin raise significant clinical, technical and ethical issues. In this review we discuss the specific issues of early scanning, counseling and determination of chorionicity prior to invasive procedures in twins. We present the available data describing the risk associated with these procedures in twins and compare data of fetal loss rate from different studies. We also discuss the issues of fetal blood sampling and late karyotyping in twin pregnancies.

Amniocentesis↗

PubMed2005

Modified natural cycle using GnRH antagonist can be an optional treatment in poor responders undergoing IVF.

PURPOSE: To investigate the efficacy of gonadotrophin-releasing hormone (GnRH) antagonist supplementation during natural cycles in poor responders undergoing IVF-ET treatment. METHODS: We retrospectively evaluated 540 cycles of 433 suitable patients who were divided by treatment protocol into modified natural, antagonist, and long agonist groups. There were 52 modified natural cycles with GnRH antagonist supplementation, 200 stimulated cycles with GnRH antagonist, and 288 long GnRH agonist cycles. Cycle characteristics and treatment outcomes were compared between the groups. RESULTS: The mean number of oocytes retrieved in the modified natural group was significantly lower than in the stimulated antagonist and long agonist groups (1.4 +/- 0.5 vs. 2.3 +/- 1.1 and 2.5 +/- 1.1, respectively, p < 0.05). The respective implantation and pregnancy rates were 10% and 14.3%, 6.75% and 10.2%, and 7.4% and 10.6%. Cycle outcome and cycle properties were similar. CONCLUSIONS: Modified natural IVF cycle with GnRH antagonist supplementation is a feasible alternative to ovarian stimulation protocols in poor responders.

Adult↗

PubMed2005

Chromosomal abnormalities and birth defects among couples with colchicine treated familial Mediterranean fever.

OBJECTIVE: To determine whether colchicine prescribed for familial Mediterranean fever is teratogenic. STUDY DESIGN: Reproductive histories were analyzed from 326 couples referred for prenatal diagnosis because 1 partner was affected. Numbers of chromosomal abnormalities and birth defects were compared with numbers expected from published rates. RESULTS: There were 901 pregnancies, and amniocentesis had been performed in 566, all but 3 conceived while taking colchicine. Seven numerical chromosomal abnormalities were found, not statistically significantly greater than the 4.99 expected from maternal age and gestation of diagnosis (P = .24): unbalanced structural abnormalities were 6, compared with 3.22 expected (P = .11). There were 7 birth defects, a considerably lower rate than reported in local malformation registers. CONCLUSION: The current policy of routine amniocentesis in pregnancies of couples taking colchicine should not be changed until sufficient data accumulates to establish whether the higher number of chromosomal anomalies in this group is significant.

Abnormalities, Drug-Induced↗

PubMed2005

Targeting the respiratory muscles of fetal sheep for prenatal gene therapy for Duchenne muscular dystrophy.

OBJECTIVE: Duchenne muscular dystrophy (DMD) is a lethal degenerative muscular disease. Fetal gene therapy may correct the primary genetic defect. Our aim was to achieve expression of a reporter gene in the respiratory muscles of early gestation fetal sheep. STUDY DESIGN: An adenovirus vector containing the beta-galactosidase reporter gene (AdRSVbetagal) was injected into the thoracic musculature (n = 3) and pleural cavity (n = 6) of fetal sheep (61-67 days' gestation) under ultrasound guidance. Tissues were harvested after 48 hours and site and intensity of beta-galactosidase expression were assessed. RESULTS: Limited transgene expression observed after a single injection was improved by multiple injections, but remained localized. Ultrasound-guided creation of a hydrothorax led to an increase in the intensity of beta-galactosidase expression (ELISA). X-gal staining and immunohistochemistry showed that vector spread was confined to the innermost intercostal musculature. CONCLUSION: Ultrasound-guided injection can deliver gene therapy vectors to the fetal pleural cavity and achieve transduction of the respiratory muscles.

Adenoviridae↗

PubMed2005

Early detection of fetal structural abnormalities.

Most published data on the detection of fetal anomalies at 11-14 weeks are from specialized centres with considerable experience in fetal anomaly scanning. However, there is still limited information on the feasibility and limitations of the screening of these anomalies compared with the now classical mid-gestation screening. This review indicates that overall, the detection rate of fetal anomalies at 11-14 weeks is 44% compared with 74% by the mid-pregnancy scan. Major abnormalities of the fetal head, abdominal wall and urinary tract, and of the umbilical cord and placenta, can be reliably detected at 10-11 weeks of gestation. Detection of other anomalies such as spina bifida, diaphragmatic hernia or heart defects is limited before 13 weeks of gestation. So far it cannot be stated that routine first trimester screening can be used on a large scale to evaluate the fetal spine and heart in the general population. In particular, in screening for congenital heart defects, the ability to perform a full cardiac examination increases from 20% at 11 weeks to 92% at 13 weeks. The early prenatal diagnosis of these anomalies may be improved by screening at 13-14 weeks rather than during the first trimester.

Congenital Abnormalities↗

PubMed2005

One hour versus two hours postprandial glucose measurement in gestational diabetes: a prospective study.

OBJECTIVE: To compare the rate of adverse perinatal outcomes among women with gestational diabetes mellitus (GDM), monitored by 1 versus 2 hour-postprandial glucose (PPG) measurements. METHODS: A total of 112 women diagnosed with GDM, by the criteria of Carpenter-Coustan, were included in the study population. Women were recruited from two different treatment settings, but were managed by the same team of health-care professionals using a standardized protocol. Allocation to treatment group was based on treatment setting. Glucose levels were measured fasting, and either 1 hour (1-hour monitoring group-target values <140 mg/dl) or 2 hours (2-hour monitoring group-target values <120 mg/dl) postprandially. Demographic data and perinatal outcomes were collected from their medical records. RESULTS: In all, 66 women were assigned to 1-hour monitoring group (1 h-PPG) and 46 women to 2-hour monitoring group (2 h-PPG). There were no differences in parity, family history of diabetes, rate of GDM in previous pregnancies, weight gain, pregestational BMI and 50-g-glucose challenge test (GCT) and 100-g oral glucose challenge test (OGTT) results. As expected, there was a significant difference in mean blood glucose levels between the two groups (108.1+/-19.2 and 94.9+/-21.2 mg/dl, 1- and 2 hours, respectively, p<0.0001); however, HbA1C levels were similar in the two groups. Perinatal outcomes were defined as gestational week at delivery; fetal weight (3325+/-471 vs 3309+/-608 g, respectively) and percentile (47.2+/-27 vs 49.6+/-30, respectively), and were similar for both groups. Insulin therapy was initiated more frequently in 2-hour monitoring group (28 and 40% of women in groups 1 and 2, respectively; p<0.05). Rates of macrosomia (7.5 versus 10.6%), large for gestational age (7.4 versus 15.2%), and delivery by cesarean section (24 versus 30%) were increased in group 2 (2 h-PPG) but these differences did not reach statistical significance. CONCLUSION: These data suggest that diet control in women with GDM managed by 1-hour PPG measurements is associated with a decreased rate of insulin therapy. However, neonatal and obstetrical outcomes are not determined by the timing of their glucose determinations.

Adult↗

PubMed2005

Elevated serum uric acid levels in gestational hypertension are correlated with insulin resistance.

The purpose of this study was to assess a possible correlation between insulin resistance and uric acid levels in gestational hypertension (GH) and preeclampsia. Fourteen pregnant, nondiabetic women with either GH (n = 7) or preeclampsia (n = 7) and nine pregnant healthy controls in the third trimester were enrolled onto the study. Fasting serum was collected and insulin sensitivity was determined by Homeostasis Model Assessment based on the algorithm developed by Turner and colleagues. Serum samples were also analyzed for creatinine and uric acid levels. Insulin resistance and uric acid levels were compared between hypertensive and control pregnant women, and the association between these two variables was calculated. There were no significant differences in mean age, weight, body mass index, and glucose challenge test between all hypertensive patients and controls. Significant differences were revealed in insulin sensitivity between hypertensive and nonhypertensive pregnant women (45 +/- 31.2% vs. 79.7 +/- 33%; p = 0.018). In our study, uric acid levels were not significantly higher for hypertensive patients (5.46 +/- 0.85 vs. 4.53 +/- 1.4 mg/dL in controls; p = 0.06). The elevated serum uric acid levels were highly correlated to insulin resistance in patients with GH. In contrast, uric acid levels did not correlate with insulin sensitivity in patients with preeclampsia and controls. Insulin resistance is associated with the elevated uric acid levels found in nonproteinuric gestational hypertensive disease.

Adult↗

PubMed2004

Fetal cardiac anomalies and genetic syndromes.

Cardiac anomalies may occur in isolation or can be part of a genetic syndrome. In this article, we describe some of the genetic syndromes commonly associated with cardiac anomalies where there are other sonographic features that may aid accurate prenatal diagnosis.

Chromosome Aberrations↗

PubMed2004

Impact and treatment of cancer during pregnancy.

Cancer is the second most common cause of death in the reproductive years and complicates up to one in 1000 pregnancies. When cancer is diagnosed during pregnancy, the management strategy must take into account both the mother and developing fetus. In this article, the four most common malignancies diagnosed in pregnant patients--cervical and breast cancer, malignant melanoma and lymphoma--will be reviewed, with an emphasis on the impact of the diagnosis and management on the pregnant patient and the developing fetus.

Adult↗

PubMed2004

Alterations in segmentary branch pulmonary artery blood flow velocimetry in fetuses of diabetic mothers.

OBJECTIVE: To evaluate pulmonary blood flow in fetuses of diabetic mothers by measuring changes in fetal segmentary pulmonary artery blood flow velocimetry throughout pregnancy. METHODS: Thirty-eight women with pregestational diabetes between weeks 18 and 38 were compared with 99 women with singleton low-risk gestations as controls. Flow velocity waveforms at the proximal middle and distal segments of the right pulmonary artery were obtained with power and color Doppler sonography in all fetuses. The pulsatility index of each segment was compared between the 2 groups. The mean value and 95% confidence interval for each segment were determined in correlation with gestational age for both groups. RESULTS: The highest mean pulsatility indices were obtained in the proximal segment of the pulmonary artery and were 2.25 in the diabetes group and 2.36 in controls. The mean pulsatility indices were significantly decreased in the middle and distal segments to 1.59 and 1.10 in the diabetes group and to 1.57 and 1.02 in controls (P < .05). There were no significant differences in pulsatility indices measured at the proximal and middle segments between the study and control groups. However, the mean pulsatility index +/- SD measured at the distal segment in the diabetic group was 9% higher than in controls (1.10 +/- 0.13 versus 1.02 +/- 0.12; P = .01). The mean pulsatility index (in the study and control groups) in each arterial segment did not change significantly throughout gestation (P > .1). CONCLUSIONS: . In human fetuses throughout gestation, the pulmonary circulation maintains stable vascular resistance in both diabetic and normal pregnancies. However, in all gestations, the pulsatility index in each segment of the pulmonary artery is unique and reflects the proximity to the heart and the impedance at each location. The significantly higher pulsatility index in the diabetes group might be related to alterations in the microcirculation of diabetic patients.

Adult↗

PubMed2004

Prenatal sonographic diagnosis of hemivertebra.

OBJECTIVE: To describe our experience in prenatal diagnosis of hemivertebra. METHODS: This is a case series of patients referred to our tertiary medical center over a 3-year period. All fetuses were scanned by high-resolution real-time scanners. The apparent vertebral anomaly was assessed in a real-time manner by a joint team of obstetricians, sonographers, and pediatric orthopedic surgeons. A complete anomaly survey of other fetal organs was performed on each fetus. All patients were given proper counseling by the same joint team. All patients had detailed obstetric and neonatal follow-up. Prenatal sonograms, neonatal medical records, and clinical courses were evaluated retrospectively. RESULTS: During the 3 years, 6 cases of hemivertebra were identified in our department. Gestational age at diagnosis was 14 to 23 weeks. Two patients had conception by assisted reproductive technology. Associated anomalies included VATER syndrome (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia), gastroschisis, and pyelectasis. Outcomes in fetuses without major associated anomalies were fair. CONCLUSIONS: Diagnosis of isolated hemivertebra might be associated with a favorable outcome. The 3 key factors in achieving an optimal spine at maturity, early diagnosis, anticipation, and prevention of deterioration, might be enhanced by our joint multidisciplinary approach to the diagnosis of skeletal anomalies.

Abnormalities, Multiple↗

PubMed2002

The role of sonographic assessment of cervical length in the prediction of preterm birth in primigravidae with twin gestation conceived after infertility treatment.

OBJECTIVE: To identify the risk factors for preterm birth in primigravidae with twin gestation and the role of transvaginal ultrasonographic assessment of the cervix. METHODS: Between January 1996 and December 1996, 54 twin pregnancies were prospectively enrolled. All women were at their first pregnancy. All women conceived following infertility treatments and all had a normal uterine cavity proven by hysterosalpingography (HSG) or hysteroscopy. Multiple logistic regression analysis was used to evaluate the association between the length of the cervix at 18-24 weeks of gestation and outcome variables, controlling for possible confounding factors. RESULTS: The mean +/- SD maternal age was 30.9 +/- 5.3 years (range 22-46), and five of them were aged 40 or more. Nine patients (20.5%) delivered prematurely, defined as spontaneous delivery at or before 34 weeks of gestation. There was no statistically significant difference between women who delivered before or after 34 weeks of gestation in regard to maternal age, body mass index (BMI), weight gain in pregnancy, smoking and work during pregnancy. The mean cervical length of patients who delivered before 34 weeks of gestation (30.1 +/- 6.1 mm) was significantly shorter than that of women who delivered after 34 weeks of gestation (42.2 +/- 6.2 mm; P < 0.001). Cervical length longer than 35 mm predicted delivery after 34 weeks of gestation with sensitivity and specificity of 88.5% and 88.9%, respectively. The positive and negative predictive values were 96.9% and 66.7%. CONCLUSION: A transvaginal ultrasonographic measurement of the cervix > 35 mm at 18-24 weeks in twin gestation can identify patients at low risk for delivery before 34 weeks. Maternal age, BMI, weights gain, smoking and work during the pregnancy did not influence the duration of the pregnancy.

Adult↗