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Biomedical subjects

M Y Divon

Publications and source records attributed to M Y Divon.

At least 37 records · Page 2Linked to original sources
PubMed1997

Neonatal nucleated red blood cell counts in small-for-gestational age fetuses with abnormal umbilical artery Doppler studies.

OBJECTIVE: The presence of elevated nucleated red blood cell counts in neonatal blood has been associated with fetal hypoxia. We sought to determine whether small-for-gestational-age fetuses with abnormal umbilical artery Doppler velocity waveforms have elevated nucleated red blood cell counts. STUDY DESIGN: Hospital charts of neonates with the discharge diagnosis of small for gestational age (birth weight < 10th percentile) who were delivered between October 1988 and June 1995 were reviewed for antepartum testing, delivery conditions, and neonatal outcome. We studied fetuses who had an umbilical artery systolic/diastolic ratio within 3 days of delivery and a complete blood cell count on the first day of life. Multiple gestations, anomalous fetuses, and infants of diabetic mothers were excluded. Statistical analysis included the Student t test, chi 2 analysis, analysis of variance, and simple and stepwise regression. RESULTS: Fifty-two infants met the inclusion criteria. Those with absent or reversed end-diastolic velocity (n = 19) had significantly greater nucleated red blood cell counts than did those with end-diastolic velocity present (n = 33) (nucleated red blood cells/100 nucleated cells +/- SD: 135.5 +/- 138 vs 17.4 +/- 23.7, p < 0.0001). These infants exhibited significantly longer time intervals for clearance of nucleated red blood cells from their circulation (p < 0.0001). They also had lower birth weights (p < 0.05), lower initial platelet count (p = 0.0006), lower arterial cord blood pH (p < 0.05), higher cord blood base deficit (p < 0.05), and an increased likelihood of cesarean section for "fetal distress" (p < 0.05). Multivariate analysis demonstrated that absent or reversed end-diastolic velocity (p < 0.0001) and low birth weight (p < 0.0001) contributed to the elevation of the nucleated red blood cell count, whereas gestational age at delivery was not a significant contributor. CONCLUSION: We observed significantly greater nucleated red blood cell counts and lower platelet counts in small-for-gestational-age fetuses with abnormal umbilical artery Doppler studies. This may suggest that antenatal thrombotic events lead to an increased placental impedance. Fetal response to this chronic condition may result in an increased nucleated red blood cell count.

Adult↗
PubMed1997

Immunophenotypic characterization of human fetal liver hematopoietic stem cells during the midtrimester of gestation.

OBJECTIVE: Our purpose was to define the extent to which gestational age influences the number of fetal liver cells that coexpress phenotypic markers associated with hematopoietic stem cells and major histocompatibility antigens. STUDY DESIGN: Fetal liver cells from abortuses of 9 to 24 weeks of gestation were studied (n = 61). Low-density nucleated liver cells were isolated on a discontinuous density gradient and subsequently incubated with antibodies that recognize markers of hematopoietic stem cells (i.e., CD33, CD34, CDw90, CD117, and CD123). Human leukocyte antigen class I (A, B, C) and class II (DR) antigens were also determined on these cells. Each sample was analyzed by immunocytochemistry and flow cytometry. Analysis of variance was used for statistical analysis. RESULTS: Of the markers measured, only the percentage of CD123-positive cells increased significantly with gestational age (p < 0.01). The percentage of triple-positive cells (CD34+, CD117+, and CD123+) increased with age but did not reach significance (p = 0.05). Human leukocyte A, B, and C antigens were expressed on all nucleated cells from 9 to 24 weeks of gestation. Human leukocyte DR antigen, however, was expressed only on 50% of these cells. The percentage of cells that expressed both hematopoietic stem cell markers and DR antigen did not vary with gestational age. CONCLUSIONS: From 9 to 24 weeks of gestation the number of human fetal liver hematopoietic stem cells that coexpress major histocompatibility antigens increases with advancing gestational age, largely because the percentage of these cells remains constant while the liver mass increases.

Adolescent↗
PubMed1997

Transvaginal sonographic imaging of early second-trimester fetal anatomy assisted by uterine fundal pressure.

OBJECTIVE: To assess the advantage of applying uterine fundal pressure to assist transvaginal sonographic imaging of early second-trimester fetal anatomy. METHODS: One hundred consecutive patients with singleton fetuses underwent routine transvaginal sonographic assessment of fetal anatomy between 13 and 17 weeks' gestation. If the entire fetal anatomy including cardiac outflow tracts was not depicted, uterine fundal pressure was applied with the operator's nonscanning hand in a bimanual fashion, to facilitate transvaginal imaging. Transabdominal sonography was performed when visualization of the entire fetal anatomy was not obtainable with transvaginal or uterine fundal pressure-assisted transvaginal sonography. Observed fetal structures with and without fundal pressure were compared. Factors assessed that may have modified the value of fundal pressure included patient weight, gestational age, fetal presentation, previous abdominal surgery, and the presence of uterine fibroids. Statistical analysis included McNemar test, chi 2, Fisher exact test, and t test, with P < .05 considered significant. RESULTS: Visualization of lower limbs, head (including intracranial structures), upper limbs, kidneys, spine, gender, feet, hands (digits), face, four-chamber view, and cardiac outflow tracts was significantly enhanced by uterine fundal pressure-assisted versus nonassisted transvaginal sonography. Uterine fundal pressure improved transvaginal sonographic imaging in 91% of subjects, and in 51% of all subjects, a complete examination was thus obtained. In 20% of all subjects, transabdominal sonography was required to complete the examination. Complete fetal anatomic scanning was unobtainable despite uterine fundal pressure supplemented by transabdominal sonography in 29% of cases. Completion of the transvaginal sonographic fetal anatomic survey with uterine fundal pressure was related to gestational age (P < .02) and maternal weight (P < .05) yet not related to fetal presentation (P = .13), previous abdominal surgery (P = .06), or uterine fibroids (P = .26). CONCLUSION: Uterine fundal pressure applied during early second-trimester transvaginal sonographic evaluation of fetal anatomy significantly improves visualization of fetal structures otherwise located beyond the effective range of the transvaginal transducer.

Adolescent↗
PubMed1997

Placental pathology of absent and reversed end-diastolic flow in growth-restricted fetuses.

OBJECTIVE: To identify placental histopathology associated with absent and reversed end-diastolic flow demonstrated by umbilical artery (UA) Doppler velocimetry in fetal growth restriction (FGR). METHODS: Between January 1989 and June 1995, 64 consecutive, nonanomalous singletons at less than the tenth percentile for birth weight were admitted to the neonatal intensive care unit, with UA Doppler velocimetry obtained within 3 days of delivery; 54 of the 64 (84%) had placental histopathology. Umbilical artery Doppler wave forms were classified as having end-diastolic flow (n = 26), and either absent (n = 20) or reversed end-diastolic flow (n = 8). Blinded review of placental histology scored lesions in categories of intraplacental vaso-occlusion, uteroplacental vascular pathology, chronic inflammation, and coagulation. RESULTS: Using cases of FGR with end-diastolic flow present as the control population, we found that absent end-diastolic flow cases had significantly more fetal stem vessels with medial hyperplasia and luminal obliteration, and cases of reversed end-diastolic flow had significantly more poorly vascularized terminal villi, villous stromal hemorrhage, "hemorrhagic endovasculitis," and abnormally thin-walled fetal stem vessels (each P < .005). CONCLUSION: In FGR, UA Doppler velocity wave forms do not demonstrate a continuum of placental lesions in which reversed end-diastolic flow reflects more severe placental histopathology than absent end-diastolic flow and end-diastolic flow present. As expected, absent end-diastolic flow cases had more occlusive lesions of the intraplacental vasculature. In reversed end-diastolic flow, lesions suggesting vascular remodeling and/or damage by pathologic conditions of intraplacental flow predominated.

Blood Flow Velocity↗
PubMed1997

Gestational diabetes and preterm labour: is glycaemic control a contributing factor?.

OBJECTIVES: (1) to evaluate the incidence of preterm delivery in patients with gestational diabetes mellitus; (2) to determine the association between glycaemic control and preterm delivery in these patients. STUDY DESIGN: (1) The incidence of spontaneous preterm singleton deliveries was determined in 550 intensively-treated patients with gestational diabetes mellitus. A total of 14 552 consecutive patients without gestational diabetes mellitus who delivered during the same interval served as a control population; (2) Glycaemic profiles (i.e., mean blood glucose, percent of hypoglycaemic [ < 60 mg/dl] and hyperglycaemic [ > 120 mg/dl] episodes) were compared in 34 patients with gestational diabetes mellitus who delivered preterm, and 68 matched controls with gestational diabetes mellitus who delivered at term. RESULTS: (1) The incidence of preterm delivery in gestational diabetics was similar to that found in the non-diabetic population (6.2% vs. 6.5%, respectively, P = 0.82; confidence limits: 0.65, 1.36); (2) women with gestational diabetes mellitus who delivered at term, or preterm had similar glycaemic profiles for both the entire treatment period and the week preceding delivery. CONCLUSIONS: (1) There is no increased risk for preterm delivery in intensively-treated gestational diabetes mellitus patients; (2) In a population such as this women with gestational diabetes mellitus who deliver preterm cannot be characterised by their glycaemic profile.

Adult↗
PubMed1997

Receiver operating characteristic curves of sonographic estimated fetal weight for prediction of macrosomia in prolonged pregnancies.

We evaluated areas under receiver operating characteristic curves for sonographic estimated fetal weight (EFW) as a predictor of macrosomia in prolonged pregnancies. These areas were 0.85 for birth weights of > or = 4000 g and 0.95 for birth weights of > or = 4500 g. Both were significantly greater than 0.5, the area under curves for useless tests. Areas under curves before and after adjustment for time elapsed between measurement and delivery did not differ significantly. At the inflexion point cut-off level of 3711 g, sensitivity, specificity and positive and negative predictive values of EFW for birth weight of > or = 4000 g were 85, 72, 49 and 94%, respectively. At the inflexion point cut-off level of 4192 g for birth weight of > or = 4500 g, these values were 83, 92, 30 and 99%. The relative risk for birth weight of > or = 4000 g was 7.99, and for birth weight of > or = 4500 g, 39.50, both significant. In conclusion, sonographic EFW is a useful test for predicting macrosomia. Adjustment for time elapsed did not significantly improve either test, probably because of slow rates of fetal growth at this gestational age. Cut-off values derived from this analysis result in high sensitivity but low positive predictive value. A randomized controlled trial of mode and timing of delivery for predicted macrosomia is needed.

Adult↗
PubMed1997

Etiologies of fetal growth restriction.

We have presented here are a long list of conditions associated with an increased incidence of fetal growth restriction. Missing from much of the literature on FGR are data that would allow more informed counseling of patients in terms of predicting their risk of carrying a pregnancy complicated by FGR. For example, very little has been published on the chances of having an infant with FGR in a woman suffering from SLE or chronic hypertension. Future studies of FGR should address these issues so that clinicians may counsel their patients properly.

Congenital Abnormalities↗
PubMed1997

Fetal growth in multifetal gestation.

Multiple gestations present a significant increase in fetal growth abnormalities in direct relationship to the number of fetuses present. Various definitions of birth weight discordancy exist (> or = 15%-40%). When first trimester discordancy in CRL or gestational sac diameter or early second trimester discordancies of BPD, HC, AC, or femur length are detected, genetic counseling and further work-up, including chromosomal analysis, should be considered. AC and SEFW are the best sonographic predictors of second and third trimester growth discordancy of twins. Discordant Doppler velocimetry of the umbilical arteries enhances ultrasonographic diagnosis of twin discordancy. Karyotyping also should be considered on second or third trimester diagnosis of growth discordancy. Twin-twin transfusion should be considered when growth discordancy is diagnosed in monochorionic gestations. Concordant twins with appropriate-for-gestational-age growth parameters should be followed with repeated sonographic assessment of fetal growth at approximately 4-week intervals. Discordant twins should be followed by repeat sonographic assessment of fetal growth at closer intervals, most probably every 2 weeks. Surviving singleton fetuses, after spontaneous fetal death of a twin at > 16 weeks of gestation, should be followed with antepartum surveillance similar to that of discordant twins. In rare cases of extremely premature twins with discordant growth and deteriorating fetal well-being of the growth-restricted twin, conservative management should be considered in favor of the normally grown fetus.

Embryonic and Fetal Development↗
PubMed1997

Noninvasive first-trimester screening for fetal aneuploidy.

We reviewed all studies concerning noninvasive first trimester screening for fetal aneuploidy obtained from a MEDLINE search through June 1996 with additional sources identified through cross-referencing. Three screening and diagnostic modalities are of potential application in noninvasive first trimester testing for fetal aneuploidy: ultrasound, maternal biochemical markers, and analysis of fetal cells retrieved from maternal sources. Sensitivities of the sonographic finding of nuchal translucency thickness in combination with maternal age for trisomy 21, performed between 10 and 14 weeks of gestation in experienced hands, and maternal biochemical markers independently may be as high as 86 percent and 60 percent, respectively. Sensitivity, specificity, and predictive values of these diagnostic modalities alone, in combination with each other, or in conjunction with other predisposing factors such as maternal age, in large low risk populations have not currently been established. Analysis of fetal cells retrieved from maternal sources, although more complex, may offer definitive noninvasive prenatal diagnosis yet is not currently available in clinical practice. We conclude that noninvasive first trimester screening for fetal aneuploidy modalities including sonographic examination for nuchal translucency thickness and maternal biochemical markers, is feasible. Clinical feasibility; and all-encompassing clinical management paradigms of these and other early noninvasive first trimester screening methods for fetal aneuploidy, are not yet available.

Aneuploidy↗
PubMed1997

Fetal testing in postdates.

Postdate pregnancies are at significant risk for perinatal morbidity. Fetal testing may be used to observe the prolonged pregnancy safely while awaiting onset of labor. Pitfalls associated with the use of fetal testing in this situation are discussed. The current literature addressing these problems is reviewed.

Amniotic Fluid↗
PubMed1996

Fetal heart rate patterns in pregnancies complicated by maternal diabetes.

OBJECTIVE: To compare the fetal heart rate (FHR) pattern between fetuses of well controlled diabetic and non diabetic mothers using a computerized analysis of FHR. STUDY DESIGN: Weekly fetal surveillance was performed in 99 fetuses of mothers with diabetes class A, 21 fetuses of mothers with diabetes class B-R, and 55 fetuses of non-diabetic women, starting at 30 weeks' gestation. All diabetic patients were well controlled. Fetal surveillance included a computerized analysis of the FHR, umbilical and uterine Doppler velocimetry, and a biophysical profile. Changes of FHR variation, frequency of FHR accelerations, and umbilical and uterine Doppler velocimetry were calculated using a regression analysis for each patient. The average slopes and the intercept at 30, 34, and 38 weeks' gestation of these variables were compared among the three groups. RESULTS: The slope of FHR variation and the frequency of accelerations had a lower rate of increase during the third trimester in fetuses of mothers with diabetes class A (0.84 +/- 0.25 ms/week and 0.06 +/- 0.02/20 min/week, respectively) compared with fetuses of non-diabetic mothers (1.34 +/- 0.55 ms/week and 0.5 +/- 0.1/20 min/week, respectively). In fetuses of mothers with diabetes class B-R, FHR variation did not change with gestation (-0.011 +/- 0.2 ms/week) with a small increase in the frequency of accelerations (0.02 +/- 0.004/20 min/week). While no differences were observed at 30 weeks' gestation, FHR variation and the frequency of accelerations were significantly reduced at 34 weeks' gestation in fetuses of mothers with diabetes class B-R compared with fetuses of non-diabetic mothers (P < 0.01). At 38 weeks' gestation, fetuses of mothers with diabetes class B-R and diabetes class A had both significantly reduced FHR variation as well as frequency of accelerations compared with fetuses of non-diabetic mothers (P < 0.01). The rate of decrease of the umbilical and uterine artery S/D ratios were similar among the three groups. CONCLUSIONS: The FHR pattern appears to be different in fetuses of well controlled diabetic mothers when related to fetuses of non-diabetic mothers. Disease specific standards should be considered for interpretation of FHR patterns in diabetic pregnancies.

Adult↗
PubMed1996

Prenatal ultrasonographic assessment of the ductus arteriosus: a review.

OBJECTIVE: To review current data pertaining to prenatal ultrasonography of the ductus arteriosus. DATA SOURCES: We reviewed manuscripts published in the English language regarding prenatal ultrasonography and the fetal ductus arteriosus obtained from a MEDLINE search for 1966 onward. Additional sources were identified through cross-referencing. METHODS OF STUDY SELECTION: Data regarding morphology, physiology, pathophysiology of fetal disease, and hemodynamic changes after administration of various maternal medications and structural congenital anomalies of the ductus arteriosus were selected. DATA EXTRACTION AND SYNTHESIS: Knowledge of the function of the ductus arteriosus in both normal and abnormal fetal conditions is enhanced by prenatal ultrasonographic findings. Detailed analyses of ductus arteriosus hemodynamics are indicated in well-defined medical conditions, including maternal medication and established structural or functional fetal cardiac disease. CONCLUSION: The fetal ductus arteriosus is a vascular structure of major functional importance. Knowledge of physiologic hemodynamic changes of blood flow in this vessel obtained by prenatal ultrasonography in conjunction with increasing gestational age, maternal medication, fetal growth restriction, as well as the detection of structural anomalies, may assist in clinical management of complicated pregnancies.

Ductus Arteriosus↗
PubMed1996

Doppler study of the fetal cardiac function in prolonged pregnancies.

OBJECTIVE: To evaluate the association between fetal cardiac function and amniotic fluid index (AFI) in postterm fetuses, and to determine if changes in fetal cardiac function precede the occurrence of nonreassuring intrapartum fetal heart rate (FHR) patterns. METHODS: Forty-five otherwise low-risk pregnant women between 41 and 43 weeks' gestation were studied longitudinally. Gestational age was confirmed in all patients by ultrasound before 20 weeks' gestation. Each subject had two or three tests performed every 3-4 days, including a non-stress test, a biophysical profile, and Doppler studies of the aortic and pulmonic outflow tracts. Aortic and pulmonic artery flow velocity waveforms were recorded slightly distal to the valves. Peak velocity, velocity time integral, and heart rate were calculated from the flow velocity waveforms we obtained. The change in AFI and aortic and pulmonic peak velocity and [velocity time integral] x [heart rate] were calculated for each fetus. RESULTS: Labor was induced at 42 weeks' gestation in 20 patients, and 17 entered labor spontaneously. Changes in AFI, observed during the follow-up period, correlated significantly with changes in aortic peak velocity (r = 0.54, P < .01) and with aortic outflow [velocity time integral] x [heart rate] (r = 0.60, P < .001) but not with pulmonic peak velocity and [velocity time integral] x [heart rate]. The decrease in aortic peak velocity and aortic and pulmonic [velocity time integral] x [heart rate] was significantly higher (P < .01) in eight fetuses that developed a nonreassuring intrapartum FHR (reduced FHR variability, late decelerations, and severe variable decelerations) than in those who had an uneventful labor. CONCLUSION: In prolonged pregnancies, cardiac function deteriorates in fetuses that develop a nonreassuring intrapartum FHR, and the changes in the left cardiac function correlate with changes in AFI.

Adult↗
PubMed1996

Prenatal ultrasonographic assessment of the ductus venosus: a review.

OBJECTIVE: To review current data pertaining to prenatal ultrasonography of the ductus venosus. DATA SOURCES: We identified English-language studies regarding prenatal ultrasonography and the fetal ductus venosus. The studies were obtained from a MEDLINE search for the period 1966 through March 1996. Additional sources were identified through cross-referencing. METHODS OF STUDY SELECTION: We reviewed all published reports, case studies, and articles regarding ultrasonographic morphology, physiology, and pathophysiology of the fetal ductus venosus. TABULATION, INTEGRATION, AND RESULTS: Knowledge of the function of the fetal ductus venosus in both normal and abnormal fetal conditions is increased by prenatal ultrasonographic data. Altered ductus venosus hemodynamics may be noted in various medical conditions that include fetal growth restriction, twin-twin transfusion, invasive diagnostic procedures (chorionic villus sampling and fetal blood sampling), fetal anemia and transfusion, complex cardiac structural anomalies, and cardiac arrhythmias. CONCLUSION: Blood flow velocity in the fetal ductus venosus reflects the pressure gradient between the umbilical vein and the cardiac atria. Knowledge of pathophysiologic hemodynamic changes of blood flow in this vessel obtainable by prenatal ultrasonography in conjunction with fetal disease may assist diagnosis and management.

Blood Flow Velocity↗
PubMed1996

Umbilical artery Doppler velocimetry: clinical utility in high-risk pregnancies.

An abnormal result of an umbilical artery Doppler study reflects the presence of placental vascular pathologic mechanisms and identifies pregnancies at increased risk for perinatal mortality. Recent reviews of the clinical utility of umbilical artery Doppler study have concluded that it should not be routinely used as a screening modality for the general obstetric population and have suggested that further research is required. However, metaanalysis of published peer-reviewed and randomized controlled trials indicates that its use in high-risk pregnancies is associated with a significant decrease in perinatal mortality without an increase in the rate of inappropriate obstetric intervention. This clinical opinion serves to underscore the relevance of umbilical artery Doppler velocimetry to clinical practice and to suggest that an abnormal result of an umbilical artery Doppler study should be added to the current list of indications for intensive fetal surveillance.

Female↗
PubMed1996

Accuracy of intrapartum estimates of fetal weight. Effect of oligohydramnios.

OBJECTIVE: To study the effect of oligohydramnios on the accuracy of intrapartum clinical and sonographic estimates of fetal weight (EFWs). STUDY DESIGN: Intrapartum clinical and sonographic EFWs and an amniotic fluid index (AFI) were obtained on 124 term patients. Oligohydramnios was defined as an AFI < or = 5 cm. RESULTS: Clinical and sonographic EFWs in women with oligohydramnios were significantly less accurate than estimates derived in patients with normal amniotic fluid: P = .03 and .02, respectively. The incidence of clinical and sonographic EFWs within +/-10% of the actual birth weight were 70.1% and 68.4%, respectively (P = NS). CONCLUSION: In term patients, intrapartum sonographic prediction of birth weight offers no advantage over estimated fetal weight obtained by abdominal palpation. The presence of oligohydramnios significantly reduces the accuracy of intrapartum clinical as well as sonographic EFWs. Therefore, we suggest that intrapartum EFWs be obtained prior to artificial rupture of the membranes.

Amniotic Fluid↗