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Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 73 records · Page 4Linked to original sources
PubMed1993

Maternal tobacco use and substance abuse: reported prevalence rates and associations with the delivery of small for gestational age neonates.

OBJECTIVE: To determine the changes in reported prevalence rates of tobacco use and substance abuse in a population of pregnant women, as well as to evaluate the associations between such use and sociodemographic characteristics and the delivery of small for gestational age (SGA) neonates. METHODS: We studied 7741 women who delivered at Cedars-Sinai Medical Center from 1986-1990. Antenatal and delivery information was entered prospectively into the computerized perinatal data base. Subjects were classified according to tobacco use and substance abuse status. We defined SGA as a birth weight less than the tenth percentile for gestational age at delivery. Univariate and multivariate analyses were used to determine the associations between SGA and tobacco use, substance abuse, and sociodemographic characteristics. RESULTS: We found that the reported prevalence rates of tobacco use and substance abuse declined between 1986-1990 (10 versus 6% and 7 versus 2%, respectively; P < .001). Tobacco use and substance abuse were reported as being highest in black women (11 and 6%) and lowest in Asian and Hispanic women (4 and 3%), a significant difference (P < .001). Tobacco use and race-ethnicity were found to have the strongest independent associations with SGA. The incidence of SGA was highest in black women identified as tobacco users and substance abusers. CONCLUSIONS: The reported rates of tobacco use and substance abuse varied by year, race-ethnicity, and insurance status. There were significant associations between maternal tobacco use, substance abuse, and race-ethnicity and the incidence of SGA neonates.

Adult↗
PubMed1993

Cigarette smoking during pregnancy: acute effects on uterine flow velocity waveforms.

OBJECTIVE: To determine the acute effects of smoking during pregnancy on selected characteristics of the flow velocity waveform of the uterine artery. METHODS: We studied 19 chronic smokers at a mean (+/- standard error) gestational age of 28 +/- 1 weeks. After informed consent was given, the uterine artery was located using ultrasound imaging with color flow mapping. The characteristic waveform was imaged by pulsed Doppler ultrasonography. Maternal heart rate and blood pressure and the systolic-diastolic ratio (S/D) and resistance index of the uterine artery were measured before (-10 and -1 minutes), during (+5 and +10 minutes), and after (+20 and +30 minutes) smoking two standard cigarettes in succession. RESULTS: Maternal heart rate increased 27%, systolic blood pressure increased 8%, and diastolic blood pressure increased 19% with smoking (P < .001). The uterine artery S/D and resistance index decreased from 2.33 to 2.02 and from 0.55 to 0.49, respectively (P < .001). CONCLUSION: The acute effects of smoking on maternal systemic hemodynamics probably influence the flow velocity waveform of the uterine artery and preclude any definitive interpretation of acute changes in downstream resistance.

Adult↗
PubMed1993

Color flow mapping and Doppler velocimetry in the diagnosis and management of a placental chorioangioma associated with nonimmune fetal hydrops.

BACKGROUND: Placental chorioangiomas are the most common tumors of the placenta, occurring in 1% of all pregnancies. With the increasing use of ultrasound, prenatal recognition of these tumors is becoming more common. CASE: A 36-year-old woman presented at 28 weeks' gestation with an intrauterine mass suggested by color flow and Doppler studies to be a vascular tumor. Because of the association of these findings to nonimmune fetal hydrops, management included umbilical blood sampling and intravascular transfusion for fetal anemia. This intervention temporarily corrected the hydrops and significantly prolonged the pregnancy. CONCLUSION: Color flow mapping and Doppler flow studies of intrauterine tumors associated with fetal nonimmune hydrops can be helpful in both diagnosis and management.

Adult↗
PubMed1992

Transvaginal ultrasound: does it help in the diagnosis of placenta previa?

The purpose of this study is to evaluate the use of transvaginal ultrasound in the diagnosis of placenta previa and to assess the risk of bleeding secondary to the placement of the vaginal transducer. Thirty-eight patients with an estimated gestational age equal to or greater than 26 weeks and the diagnosis of suspected placenta previa gave their consent and were randomized to two groups. Randomization was stratified by patient weight and anterior or posterior placental location. Group 1 (n = 20) had complete obstetric ultrasounds using linear and sector transducers. Group 2 (n = 18) had similar examinations followed by transvaginal ultrasound scans. Patients were rescanned to follow placental location and fetal growth parameters. On abdominal ultrasound, the posterior placenta (n = 17) was often shadowed by fetal parts. The ease of placental visualization was rated on a four-point scale with 1 being the clearest. The mean clarity score for posterior placentas on abdominal ultrasound in Group 2 was 1.6 and on transvaginal ultrasound was 1.0, p < 0.04. The use of transvaginal ultrasound consistently revealed greater clarity of diagnosis in these patients. No patient in either group experienced increased vaginal bleeding following the scanning sessions. Transvaginal ultrasound was most beneficial for those patients with posterior placenta previas because of increased clarity of diagnosis, decreased time of scanning, and no increased incidence of hemorrhage.

Clinical Trial↗
PubMed1992

The California Maternal Serum alpha-Fetoprotein Screening Program: the role of ultrasonography in the detection of spina bifida.

Between January 1988 and June 1990, 161 cases of open spina bifida were identified by the California Maternal Serum alpha-Fetoprotein Screening Program. Eight percent of these cases were not diagnosed by an initial ultrasonographic evaluation. Three defects were not recognized until birth. Ultrasonography is inadequate to identify all cases of open spina bifida.

California↗
PubMed1992

The use of a neural network for the ultrasonographic estimation of fetal weight in the macrosomic fetus.

The error associated with regression analysis methods for the ultrasonographic estimation of fetal weight in the suspected macrosomic fetus, approximately 10%, is clinically unacceptable. This study was undertaken to evaluate the applicability of an emerging technique, biologically simulated intelligence, to this problem. One hundred patients with suspected macrosomic fetuses underwent ultrasonographic measurements of biparietal diameter, head and abdominal circumference, femur length, abdominal subcutaneous tissue, and amniotic fluid index. The biologically simulated intelligence model included gestational age, fundal height, age, gravidity, and height. The model was then compared with results obtained from previously published formulas relying on the abdominal circumference and femur length. The biologically simulated intelligence yielded an average error of 4.7% from actual birth weight, statistically better (p = 0.001) than the results obtained from regression models.

Body Weight↗
PubMed1992

Maternal phenylketonuria collaborative study, obstetric aspects and outcome: the first 6 years.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal morbidity associated with maternal hyperphenylalaninemia in women of childbearing age with blood phenylalanine levels greater than 240 mumol/L (greater than 4 mg/dl) on an unrestricted diet. STUDY DESIGN: Two hundred thirteen pregnant women with hyperphenylalaninemia that resulted in 134 live births have been enrolled in the study. Outcome measures were subject to the chi 2 test, Fisher exact test, analysis of variance, t test, or Wilcoxon nonparametric test for analysis. RESULTS: Optimal fetal outcome appeared to occur when blood phenylalanine levels less than 600 mumol/L (less than 10 mg/dl) were achieved by 8 to 10 weeks' gestation and maintained throughout pregnancy (trimester averages of less than or equal to 360 mumol/L (less than or equal to 6 mg/dl). Initiation of dietary therapy during the third trimester of pregnancy appears to have little beneficial effect on the fetus. CONCLUSIONS: Preconceptual counseling and early entrance into a prenatal care program is essential in achieving optimal fetal outcome in women with hyperphenylalaninemia.

Congenital Abnormalities↗
PubMed1992

Prenatal diagnosis of human parvovirus B19 in nonimmune hydrops fetalis by polymerase chain reaction.

OBJECTIVE: Nonimmune hydrops fetalis is a potentially lethal condition reflecting the clinical manifestation of several pathologic processes. Recently maternal infection by human parvovirus B19 has been reported to result in nonimmune fetal hydrops. We sought to develop a rapid and sensitive test to detect the presence of this agent in utero. STUDY DESIGN: Using a cloned isolate of the virus, we developed an assay based on enzymatic amplification of a segment of the human parvovirus B19 genome that allows direct detection of this agent in samples of fetal blood and amniotic fluid. RESULTS: The method detected as few as 100,000 genome equivalences and was specific for the viral genome alone. We used this assay to evaluate nine fetuses initially seen with nonimmune hydrops. Three cases were found to be positive for the human parvovirus B19 genome. CONCLUSION: The method is powerful in that it is rapid, sensitive, and simple. This assay may have general applicability in evaluation of nonimmune hydrops and in documentation of the natural history of fetal human parvovirus infections.

Erythema Infectiosum↗
PubMed1992

Screening for Down syndrome with the femur length/biparietal diameter ratio: a new twist of the data.

OBJECTIVE: The purpose of this study was to determine the value of discordant morphometric measurements as identifiers of Down syndrome by evaluating the relationship of biparietal diameter, femur length, biparietal diameter/femur length ratio, and cephalic index between a group of fetuses with trisomy 21 and a control population. STUDY DESIGN: Biometric measurements from 48 fetuses with trisomy were reviewed and compared with 107 normal fetuses of similar gestational age. Data were analyzed in 2-week gestational age intervals to determine the effect of gestational age on ultrasonographic detection of Down syndrome. Outcome measures were subject to least-squares linear regression and the t test for analysis. RESULTS: A positive relationship between abnormal morphometric measurements and fetuses with Down syndrome was detected but only during specific weeks of pregnancy. CONCLUSION: Although it appears that biometric measurements may be useful for Down syndrome, further study is needed before its widespread introduction into clinical practice.

Down Syndrome↗
PubMed1992

The effect of altitude on the umbilical artery Doppler resistance.

This study examined whether there were differences between the umbilical artery systolic-diastolic (S/D) ratio and resistance index (RI) in patients with normal fetuses living at sea level (group I) and those living between 4,200 and 4,500 feet above sea level (group II). Linear regression demonstrated a significant association (P less than 0.001) between gestational age and the S/D ratio and RI for groups I (n = 100) and II (n = 128). Least-squares regression analysis demonstrated no significant differences in slopes or intercepts between groups I and II. The results would suggest that altitude, up to 4,500 feet above sea level, does not affect umbilical artery Doppler resistance in normal fetuses.

Altitude↗
PubMed1992

Ultrasound detection of genetic anomalies.

The prenatal detection of genetic diseases has improved remarkably. This review highlights several diagnoses that are possible to identify by ultrasound examination of the fetus, including cystic fibrosis, skeletal dysplasias, kidney diseases, cardiac disease and central nervous system disorders. Ultrasound clues to the possible existence of several syndromes and aneuploidy are also outlined.

Chromosome Aberrations↗
PubMed1992

The ultrasound triad of fetal hydramnios, abnormal hand posturing, and any other anomaly predicts autosomal trisomy.

Our definition of hydramnios is an amniotic fluid index of 24 cm or greater. We evaluated by ultrasound examination 49 consecutive patients who met this definition of hydramnios. Of these, 22 (44.9%) had anomalies visible by ultrasound. The combination of hydramnios, abnormal hand posturing, and any other anomaly created a constellation of sonographic findings enabling us to predict six specific autosomal trisomies (27.27%): three trisomy 18, two trisomy 21, and one trisomy 13. The 27 fetuses with "idiopathic hydramnios" (no identifiable anomaly or abnormal hand posturing) had normal karyotypes. We recommend that any patient with confirmed hydramnios have a detailed ultrasound examination by an experienced sonographer, with special attention paid to the heart, face, and hands. If no abnormality is seen and the hands are normally postured, expectant management may be appropriate. If the late second- or third-trimester fetus displays abnormal hand posturing with any other abnormality, rapid karyotyping by funipuncture or placental biopsy should be recommended to facilitate appropriate management.

Chromosomes, Human, Pair 13↗
PubMed1991

The use of fetal echocardiography for predicting intrapartum fetal heart rate patterns in the post-term pregnancy.

One of the shortcomings of antepartum testing in the post-term pregnancy is that it does not identify the majority of fetuses who develop abnormal intrapartum fetal heart rate changes. The purpose of this study was to determine whether antenatal cardiovascular evaluation could aid in the identification of post-term fetuses at risk for intrapartum heart rate abnormalities. Seventy-five patients with a gestational age greater than 41 weeks underwent a non-stress test, amniotic fluid index and real-time assessment of the heart for the presence or absence of a pericardial effusion. M-mode measurements of the right ventricular inner dimension (RVID), left ventricular inner dimension (LVID), biventricular outer dimension (BVOD) and Doppler velocimetry of the umbilical artery (S/D) were performed. Group I (n = 32) had normal intrapartum heart rate tracings. Group II (n = 20) had abnormal intrapartum fetal heart rate tracings but did not undergo emergency delivery. Group III (n = 23) had abnormal intrapartum fetal heart rate tracings but underwent emergency delivery. When comparing Group I with Group II, the latter had significant differences for abnormal RVID, RVID/LVID ratio, and pericardial effusion. When comparing Groups I and III, there were significant differences for RVID, RVID/LVID ratio, pericardial effusion, BVOD, LVID and amniotic fluid index. Neither the non-stress test nor S/D predicted abnormal intrapartum fetal heart rate patterns. For prediction of abnormal intrapartum heart rate patterns, the sensitivities of the RVID (0.79), LVID (0.33), RVID/LVID ratio (0.72) and BVOD (0.63) were 1.7-4 times greater than the non-stress test (0.19) and the sensitivities of the RVID, RVID/LVID ratio and BVOD were 2 times greater than the amniotic fluid index (0.28). The positive (0.50-0.86) and negative (0.42-0.68) predictive values were similar for all groups. To predict emergency delivery associated with abnormal heart rate tracings, the sensitivities of the RVID (0.83), RVID/LVID ratio (0.70) and BVOD (0.65) were 2.5-3 times greater than the non-stress test (0.26) and 1.5 times greater than the amniotic fluid index (0.39). The positive (0.36-0.56) and negative (0.70-0.86) predictive values were similar. The presence of pericardial effusion had a higher sensitivity than the non-stress test and amniotic fluid index for predicting abnormal intrapartum heart rate patterns but not emergency delivery. Doppler velocimetry of the umbilical artery had a lower sensitivity than the non-stress test and amniotic fluid index for predicting intrapartum heart rate patterns as well as identifying the fetus needing emergency delivery. The results of this study would suggest that there is initially dilatation of the right ventricle which may be associated with abnormal intrapartum fetal heart rate patterns. However, when the left ventricle dilates, leading to cardiomegaly, there is a greater incidence of abnormal intrapartum fetal heart rate changes and associated emergency delivery. The amniotic fluid index appears to be a later finding for predicting abnormal intrapartum fetal heart rate changes.

Journal Article↗
PubMed1991

Leveling out.

Explore the source record for details and available documents.

Editorial↗
PubMed1991

The fetal mandible measurement: an objective determination of fetal jaw size.

The sonographic diagnosis of micrognathia has been limited by the lack of an objective measurement of the fetal mandible. A cross-sectional study of 134 normal patients of known gestational age between 14 and 39 weeks' gestation was performed. Models to predict mandible length based on gestational age, biparietal diameter, head circumference or femur length were derived by least squares regression analysis. The 95% prediction limits were also derived. Utilization of these curves generated from a normal population should allow for a more sensitive and reproducible method to diagnose micrognathia in the fetus.

Journal Article↗
PubMed1991

Congenital gastric teratoma in Wiedemann-Beckwith syndrome.

Wiedemann-Beckwith syndrome (WBS) may be associated with abdominal tumors, including Wilms tumor, adrenocortical carcinoma, hepatoblastoma, gonadoblastoma, rhabdomyosarcoma, and neuroblastoma. We report on a newborn infant with WBS and a congenital teratoma of the stomach. This is the sole report of any teratoma being associated with WBS and also the first report of a tumor present at birth and visible prenatally in WBS. At birth this infant boy had the diagnostic findings of WBS with macroglossia, ear lobule creases and pits, nevus flammeus, and omphalocele, and an abdominal mass. Abnormalities were detected prenatally when ultrasound examination showed placental overgrowth, polyhydramnios, omphalocele, and posterior abdominal calcifications. Resection of the mass and partial gastrectomy were performed at age 10 days; histologic study showed an immature grade-II teratoma containing a mixture of mature and immature tissues from all germ layers. Results of cytogenetic studies of blood and teratoma were normal (46,XY). This congenital gastric teratoma in a newborn boy with classical WBS may represent either a tumor or an included twin. We discuss its implications for the association of WBS with neoplasia and monozygotic (MZ) twinning, review various neoplasias associated with WBS, and consider pathogenetic mechanisms.

Beckwith-Wiedemann Syndrome↗
PubMed1991

Attitudes on the ethics of abortion, sex selection, and selective pregnancy termination among health care professionals, ethicists, and clergy likely to encounter such situations.

The ethical attitudes of health care providers toward abortion, sex selection, and selective termination of normal and anomalous fetuses in singleton or multiple pregnancies were evaluated by questionnaires distributed to members of the American Society of Human Genetics, the International Fetal Medicine and Surgery Society, the Society of Perinatal Obstetricians, ethicists, and clergy. Demographic characteristics of respondents exhibited a preponderance of men (76%), age greater than 40 (68%), and of United States residents (82%). Seventy-nine percent of respondents were in the medical profession. Approximately half of the respondents were Protestant, the rest being evenly distributed among Catholic, Jewish, and other religions. Acceptance of abortion for social indication varied by religion and gestational age but not by religious conviction, age, country, or gender of respondent. First-trimester abortion of a normal singleton pregnancy was considered more acceptable than selective termination of normal fetuses in multifetal gestations. Sex selection was considered unethical by most respondents. Selective termination was deemed ethically appropriate in quadruplets or multifetal gestations of more than five fetuses and in multiple pregnancies bearing one anomalous fetus. In the latter situation, acceptance increased with the severity of fetal anomalies and decreased from the first to the third trimester. The medical specialty of respondents was the only independent factor strongly associated with acceptance of selective termination by trimester, indication, and number of fetuses. Acceptance of selective termination among health care professionals appears to reflect not only perceptions of procedure-related risks and benefits in the index pregnancy but also individual training and religious beliefs.

Abortion, Induced↗