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Biomedical subjects

M Y Divon

Publications and source records attributed to M Y Divon.

At least 19 recordsLinked to original sources

Fetal and neonatal mortality in the postterm pregnancy: the impact of gestational age and fetal growth restriction.

OBJECTIVE: Our purpose was to examine the impact of gestational age and fetal growth restriction on fetal and neonatal mortality rates in the postterm pregnancy. STUDY DESIGN: All deliveries occurring in Sweden between Jan. 1, 1987, and Dec. 31, 1992, were evaluated for participation in this study. Data were derived from the National Swedish Medical Birth Registry. Pregnancies were selected for inclusion in the study on the basis of the following criteria: (1) singleton pregnancy, (2) reliable dates, (3) gestational age > or = 40 weeks, and (4) maternal age 15 to 44 years. Fetal growth restriction was defined as birth weight <2 SD below the mean for gestational age. A total of 181,524 pregnancies met the inclusion criteria and formed the study population. Fetal and neonatal mortalities at 40 weeks' gestation were used as reference levels. Logistic regression analysis was used to estimate the independent effects of gestational age and fetal growth restriction on fetal and neonatal mortality rates. RESULTS: A significant rise in the odds ratio for fetal death was detected from 41 weeks' gestation and on (odds ratios 1.5, 1.8, and 2.9 at 41, 42, and 43 weeks, respectively). Odds ratios for neonatal mortality did not demonstrate a significant gestational age dependency. Fetal growth restriction was associated with significantly higher odds ratios for both fetal and neonatal mortality rates at every gestational age examined (with odds ratios ranging from 7.1 to 10.0 for fetal death and from 3.4 to 9.4 for neonatal death). CONCLUSIONS: Postterm pregnancies have long been considered to be at high risk for adverse perinatal outcome. This study documents a small but significant increase in fetal mortality in accurately dated pregnancies that extend beyond 41 weeks of gestation. This study also demonstrates that fetal growth restriction is independently associated with increased perinatal mortality in these pregnancies.

Adolescent

Prenatal sonographic findings associated with sporadic subcortical nodular heterotopia.

BACKGROUND: Subcortical nodular heterotopia is a neuronal migration disorder of uncertain etiology. This disorder occurs primarily in females and has a familial X-linked dominant inheritance pattern. The predominant symptom associated with heterotopia is seizures. CASE: At 23 weeks' gestation, prenatal sonography disclosed an isoechoic supratentorial intracranial mass causing right-sided shift of midline structures and compression of the contralateral cerebral ventricle. Serial ultrasound examinations of this mass were significant for the absence of invasion into surrounding structures, gross enlargement of cranial biometric parameters, and hydrocephalus and hydrops fetalis. Neonatal magnetic resonance imaging findings were consistent with gray matter heterotopia and were confirmed as such by brain biopsy. CONCLUSION: Subcortical nodular heterotopia manifested unique prenatal sonographic findings. This case suggests the possibility of prenatal diagnosis in families at risk for this lesion.

Adult

Fetal growth restriction at term: myth or reality?

OBJECTIVE: To evaluate the morbidity and mortality associated with the small for gestational age (SGA) fetus born at term to an otherwise uncomplicated pregnancy. METHODS: Small for gestational age, singleton newborns (birth weight below the tenth percentile for gestational age) born at 37-42 weeks' gestation were identified by medical record discharge coding. We excluded gestations complicated by structural or chromosomal abnormalities, maternal diabetes mellitus, preeclampsia, chronic hypertension, asthma, or renal, endocrine, or autoimmune disease. Three low-risk, appropriate for gestational age (AGA) fetuses, matched for gestational age at delivery, were selected randomly for each SGA fetus and served as controls. Maternal and neonatal data were abstracted via medical record review. Statistical analysis included chi2 Fisher exact test, and analysis of variance. RESULTS: There were 67 newborns in the study group and 201 in the control group. There were no fetal or neonatal deaths in any of these cases. The maternal age at delivery, prepregnancy weight, race, smoking status, weight gain during pregnancy, and neonatal gender did not statistically differ between the two groups. Compared with AGA infants, a larger proportion of SGA newborns had low 1-minute Apgar scores and SGA newborns were more likely to be admitted to the neonatal intensive care unit, and have respiratory distress, hypoglycemia, thrombocytopenia, and hyperbilirubinemia. They were also significantly more likely to be delivered by cesarean. CONCLUSION: The SGA newborn from an uncomplicated pregnancy delivered at term has increased neonatal morbidity compared with its AGA counterpart. These results dispute the notion that term growth restriction is a benign condition.

Adult

Transvaginal sonography of the forewaters in the assessment of amniotic fluid volume in patients with oligohydramnios.

OBJECTIVE: To determine whether the forewaters should be considered in the assessment of amniotic fluid (AF) volume in patients beyond 37 weeks' gestation. METHODS: Sixty patients were prospectively studied and designated as having oligohydramnios or normal AF volume based upon on the standard four-quadrant AF index (AFI) of < or = 5 cm or > 5 cm, respectively. The distance between the internal os and the fetal head was measured transvaginally. This measurement was first added to the standard AFI and subsequently interchanged with the lowest of the two lower abdominal quadrant measurements. Statistical analysis included Student's t-test with p < 0.05 considered significant. RESULTS: Thirty patients were classified as oligohydramnios and 30 normal AF volume. The two subgroups did not differ as to maternal age, parity, gestational age at sonographic examination, incidence of meconium-stained amniotic fluid or 5-min Apgar scores < 7, or birth weight. No significant difference was noted between the mean forewaters measurement of patients with oligohydramnios and controls (0.2 +/- 0.1 and 0.4 +/- 0.1 cm, respectively). In patients with oligohydramnios, there was no significant difference between the standard AFI and the AF volume with the forewaters in each of the methods assessed (2.7 +/- 0.3, 2.9 +/- 0.3, and 2.7 +/- 0.3 cm, respectively). CONCLUSION: We conclude that various permutations of the AFI, which include sonographic assessment of the forewaters, do not impact on the diagnosis of oligohydramnios.

Abdomen

Uncomplicated baseline fetal tachycardia or bradycardia in postterm pregnancies and perinatal outcome.

OBJECTIVE: to assess perinatal outcome in post-term pregnancies in which fetal heart rate (FHR) monitoring revealed either uncomplicated baseline fetal tachycardia (> or = 160 bpm) or fetal bradycardia (< or = 120 bpm). STUDY DESIGN: We performed a case-control study of patients who underwent fetal assessment between July 1989 and June 1995, as part of post-term evaluation. Inclusion criteria consisted of nonlaboring afebrile patients with singleton post-term pregnancies > or = 41 weeks of gestation by strict dating criteria (last menstrual period consistent with ultrasound biometric parameters obtained prior to 20 weeks' gestation), normal fetal anatomy, intact membranes, and reactive nonstress test with no evidence of chorioamnionitis. Patients with fetal tachy or brady arrhythmias, FHR decelerations, or loss of short-term beat-to-beat variability were excluded. Baseline FHR was recorded retrospectively by an observer blinded to maternal and neonatal clinical outcome. For each case of uncomplicated baseline fetal tachycardia (> or = 160 bpm) or bradycardia (< or = 120 bpm), either two or three control cases (matched for maternal age and parity), with FHR > 120 bpm and < 160 bpm, were identified. Outcome variables assessed included: incidence of cesarean delivery, nuchal cord at delivery, meconium-stained amniotic fluid (AF), 5-min Apgar score < 7, fetal growth restriction (< 10th percentile for 41 weeks' gestation), meconium aspiration syndrome, and neonatal intensive care unit (NICU) admission. Statistical analysis included two-tailed t-test and chi2 test when appropriate, with p < 0.05 considered significant throughout. RESULTS: During the study period 1390 post-term patients (6.81% of the general population) were assessed. Of these, 31 (2.23%) fetuses exhibited baseline FHR > or = 160 bpm, and 76 fetuses (5.46%) exhibited baseline FHR < or = 120 bpm. No significant differences were noted in the incidence of cesarean delivery, presence of nuchal cord at delivery, meconium-stained AF, 5-min Apgar scores < 7, fetal growth restriction, meconium aspiration syndrome, or the incidence of NICU admissions between the groups of patients with fetal tachycardia, bradycardia, and their respective controls. CONCLUSIONS: Uncomplicated baseline fetal tachycardia or bradycardia in postterm patients are not associated with an increase in the incidence of adverse perinatal outcome.

Bradycardia

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

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

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

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

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

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

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

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

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

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

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