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Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 145 records · Page 8Linked to original sources
PubMed1986

Identification of the small for gestational age fetus with the use of gestational age-independent indices of fetal growth.

This study reviews the roles of sonographic assessment of the rate of growth of the fetal abdominal circumference, the femur length/abdominal circumference ratio, and qualitative determination of amniotic fluid volume as gestational age-independent indices for identification of the small for gestational age fetus. The sensitivity and specificity for single and combinations of test results were evaluated in 50 appropriate for gestational age and 40 small for gestational age fetuses. Positive and negative predictive values were derived for the general population. Our results indicate that either a rate of growth of the fetal abdominal circumference less than or equal to 10 mm/14 days or a femur length/abdominal circumference ratio greater than or equal to 23.5 correctly identifies most small for gestational age fetuses. When the general population is screened, only 15% of small for gestational age fetuses will be missed by this combination of criteria. The presence of a pocket of amniotic fluid less than or equal to 2.0 cm is highly suggestive of a small for gestational age fetus. However, the presence of a pocket of amniotic fluid greater than 2.0 cm does not guarantee an appropriate for gestational age fetus. We conclude that these gestational age-independent indices of fetal growth offer useful tools for differentiating between the small for gestational age and appropriate for gestational age fetus.

Amniotic Fluid↗
PubMed1986

Diminished respiratory sinus arrhythmia in asphyxiated term infants.

Spectral analysis techniques were used to quantitate the association between respiration and heart rate variability in eight healthy and eight asphyxiated infants born at term gestation. Respiratory sinus arrhythmia was demonstrated in all healthy infants. This arrhythmia was significantly diminished in asphyxiated newborn infants. We conclude that newborn infants with low Apgar scores have a reduced respiratory sinus arrhythmia and that this reduction could account for the loss of short-term heart rate variability commonly associated with asphyxia.

Apgar Score↗
PubMed1986

Fetal echocardiography. VI. Assessment of cardiothoracic disproportion--a new technique for the diagnosis of thoracic hypoplasia.

Fifty-eight fetuses were studied with use of diagnostic real-time and M-mode ultrasound between 15 and 40 weeks of gestation in which the chest circumference, biventricular outer dimension of the heart, biparietal diameter, head circumference, abdominal circumference, and femur length were measured. The chest circumference correlated with the biparietal diameter (r = 0.978), head circumference (r = 0.977), abdominal circumference (r = 0.989), femur length (r = 0.983), and biventricular outer dimension (r = 0.972). Regression analysis with predicted mean and 95% and 5% confidence limits demonstrated a linear relationship between the chest circumference and the following: biparietal diameter, head circumference, abdominal circumference, femur length, and biventricular outer dimension. Four representative cases (triploidy [69,XXX], osteogenesis imperfecta, intrauterine growth retardation, and renal agenesis) illustrate the usefulness of the data when thoracic hypoplasia is suspected.

Abdomen↗
PubMed1986

Factors influencing nonstress test results in multiple gestations.

The nonstress test remains the most widely used method of antepartum fetal health assessment in multiple gestations. However, few data are available on factors influencing its results in those cases. Our observation on 530 such tests has shown results similar to those in singleton gestations. Prematurity was associated with a higher rate of nonreactive tests; however, order and mode of presentation had no impact.

Female↗
PubMed1986

Altered fetal growth and development in a patient with Turner's syndrome.

Fertility in cases of Turner's syndrome is rare. In cases where conception does occur, spontaneous abortion and structural and chromosomal defects commonly are discovered. A review of the literature and a case report are presented in which pregnancy was complicated by severe intrauterine growth retardation and musculoskeletal deformities of the fetus.

Abnormalities, Multiple↗
PubMed1986

Role of amniocentesis in ultrasound-detected fetal malformations.

Sixty-three patients with antenatally diagnosed fetal malformations over the period of 14 months were prospectively offered genetic amniocentesis, irrespective of gestational age. An additional 15 patients were excluded from the study because of a known lethal malformation (13 anencephaly, two amniotic bands). Twenty patients accepted amniocentesis, and seven chromosomal disorders were found. Obstetric management was altered in some of these patients as a result of the anomalies.

Adult↗
PubMed1985

A prospective trial of the fetal biophysical profile versus the nonstress test in the management of high-risk pregnancies.

A randomized prospective trial study was developed to determine the diagnostic value of the fetal biophysical profile in relationship to the nonstress test. The diagnostic values of these tests were assessed in terms of the incidence of abnormal outcome. In addition comparisons between the positive and negative predictive values of each of these tests as well as the sensitivity and specificities of the test were reviewed. A total of 652 patients were entered into the study and a total of 1628 tests were performed. Of the group 279 pregnancies were managed by a biophysical profile protocol and 373 by the nonstress test protocol. Results of this study suggest that except for the negative predictive value in the sensitivities in the outcome parameters of low 5-minute Apgar scores the diagnostic values for all outcome parameters were consistently higher in the fetal biophysical profile as opposed to the nonstress test group. While higher, only two of the values, positive predictive value of overall abnormal outcome and negative predictive value of small for gestational age infants, were statistically significant. While this general trend suggests that the biophysical profile is more predictive in diagnosing fetal condition than the nonstress test, because statistical significance was not reached in all parameters further study is warranted.

Amniotic Fluid↗
PubMed1985

Lung profiles in the isoimmunized pregnancy.

The management of an isoimmunized pregnancy, although not commonly seen today, represents a challenging obstetric problem. The knowledge of fetal lung maturity status is essential in deciding when to perform an intrauterine transfusion, give steroids, or deliver an infant. The interpretation of the fetal lung profile in these patients has been questioned. Charts were reviewed from 99 isoimmunized patients cared for at Los Angeles County/University of Southern California Medical Center, Women's Hospital, from March, 1981, through December, 1983. There were 77 patients who underwent 260 amniocenteses. The lecithin-sphingomyelin ratio, dipalmitoyl phosphatidylcholine, phosphatidylinositol, and phosphatidylglycerol from the amniotic fluid did not differ from the values expected in normal gestations. There were a total of six patients who underwent intrauterine transfusions and the lung profile data were consistent with anticipated values. We conclude that lung maturation is neither delayed nor accelerated in the isoimmunized pregnancy.

Amniotic Fluid↗
PubMed1985

Evoked fetal startle response: a possible intrauterine neurological examination.

The fetal startle reflex was studied in an attempt to provide an objective and quantitative estimate of the fetal neurological condition. This reflex is a normal response to a combined sound-vibratory stimulus in the healthy infant born after 30 weeks of gestation. It consists of a generalized paroxysmal motion that involves the whole body. Thirty women with uncomplicated pregnancies, who subsequently delivered healthy infants, were studied at term. Fetal movements were monitored by means of a real-time scanner. Placement of the transducer was such that it allowed for visualization of the long axis of the fetal forearm. A 3-second stimulus was delivered on the maternal abdomen over the fetal head with use of an artificial larynx. This device generates a mixed sound-vibratory output of 100 dB and 85 Hz. Sufficient visualization of the plane of forearm motion was possible 68% of the time, thus allowing for measurement of the duration of this motion. The results indicate that the mean duration of forearm motion in response to a 3-second sound-vibratory stimulus is 8.2 +/- 2.3 seconds (+/- SEM). Since an immediate forearm motion was detected each time that a stimulus was applied, we conclude that the startle reflex does indeed exist in the fetus. This simple means of assessing the neurological state of the fetus may provide a way to evaluate fetal tone as it applies to antenatal fetal assessment.

Acoustic Stimulation↗
PubMed1985

Modification of fetal intraventricular amniotic shunt.

The benefits of fetal intraventricular amniotic shunt remain unknown. Nevertheless, the use of this technique has been described by several authors. One of the potential complications arising from its placement is the inability to retract the catheter once it is placed through the large needle. This communication describes a modification of the shunt procedure. A suture placed through the distal end of the catheter allows retrieval of the catheter shunt for as long as the needle remains in place.

Amniotic Fluid↗
PubMed1985

Fetal echocardiography. V. M-mode measurements of the aortic root and aortic valve in second- and third-trimester normal human fetuses.

The aortic root dimension and aortic valve excursion of 43 normal fetuses were recorded with M-mode echocardiography and the measured dimensions correlated with noncardiac measurements (biparietal diameter, head circumference, abdominal circumference, and femur length) and cardiac measurements (diastolic biventricular inner dimension, diastolic left ventricular internal dimension, and mitral valve excursion). The correlation coefficients for the aortic root dimension ranged between 0.87 and 0.95, while those for the aortic valve excursion ranged between 0.78 and 0.87. Regression analysis demonstrated that the best fit of the data was a linear model from which the 5% and 95% confidence limits were computed for individual predictions of aortic root dimension and aortic valve excursion from noncardiac and cardiac measurements.

Aorta↗
PubMed1985

Dynamics of human chorionic gonadotropin, prolactin, and growth hormone in serum and amniotic fluid throughout normal human pregnancy.

This study was performed to establish the dynamics of human chorionic gonadotropin, prolactin, and growth hormone throughout pregnancy in serum and amniotic fluid. Two hundred fifty healthy women at 8 to 42 weeks' gestation were studied. The highest serum human chorionic gonadotropin level was measured between weeks 8 to 12 (53,715 +/- 3574 mIU/ml, mean +/- SEM), with a decline to a mean plateau of 11,806 +/- 1250 mIU/ml from week 18. Amniotic fluid human chorionic gonadotropin had a similar pattern with a mean of 68,100 +/- 8422 mIU/ml at weeks 8 to 10, declining from week 18 to a plateau of 2005 +/- 260 mIU/ml. Human chorionic gonadotropin showed a significant correlation (r = 0.85, p less than 0.001) between levels of both compartments demonstrating an even distribution. Prolactin levels showed a dichotomy of patterns and levels. Serum prolactin showed a continuous rise from 45.3 +/- 14 ng/ml at week 8 to 224 +/- 20 ng/ml at week 36. In contrast, amniotic fluid prolactin remained low until week 14 (33.1 +/- 0.8 ng/ml), followed by a sharp and significant (p less than 0.001) increase to a plateau of 3750 +/- 200 ng/ml between weeks 18 to 26, declining to a second plateau of 500 +/- 50 ng/ml at week 36. Serum growth hormone increased from a mean of 3.5 +/- 1.4 ng/ml seen at weeks 8 to 10 to a mean of 14 +/- 2.0 ng/ml at weeks 28 to 30, followed by a plateau of similar levels. The pattern of growth hormone secretion in amniotic fluid demonstrated a sharp increase during the 14-16 interval with a maximum mean level of 15.5 +/- 1.5 ng/ml and a slow steady decline thereafter. In conclusion, the similar pattern and concentration of human chorionic gonadotropin throughout pregnancy in both maternal and amniotic fluid are probably the result of direct human chorionic gonadotropin diffusion from the placenta. The dissimilar pattern and concentration of prolactin are the result of two different sources of prolactin secretion during pregnancy. Serum prolactin originates from the pituitary and amniotic fluid prolactin from the decidua. Since the pattern of growth hormone secretion resembles that of prolactin, it is possible that growth hormone, like prolactin, is secreted by the same sources.

Amniotic Fluid↗
PubMed1985

Respiratory sinus arrhythmia in the human fetus.

This study explores the relationship between fetal heart rate variability and fetal breathing movements in the term fetus. Fourier analysis was applied to fetal heart rate variability during fetal breathing and nonbreathing episodes. A distinct component in the order of 0.7 to 0.95 Hz was demonstrated in fetal heart rate variability during breathing episodes. These frequencies have the same distribution as the corresponding rate of breathing and therefore indicate that respiratory sinus arrhythmia exists in the term fetus.

Electrocardiography↗
PubMed1985

The role of ultrasound assessment of amniotic fluid volume in the management of the postdate pregnancy.

Antepartum assessments of amniotic fluid volumes and their relationship to nonstress test patterns and pregnancy outcomes were retrospectively analyzed in 234 postdate pregnancies. The incidence of clinical oligohydramnios and a nonstress test revealing fetal heart rate deceleration or bradycardia was found to increase as the sonographic estimates of the amniotic fluid volume decreased. Furthermore, the postdate pregnancy with sonographic evidence of an adequate amniotic fluid volume had a significantly better perinatal outcome than the pregnancy without an adequate fluid volume. These results suggest that the postdate pregnancy with evidence of reduced amniotic fluid volume should be considered for a trial of labor with continuous electronic fetal monitoring.

Amniotic Fluid↗
PubMed1985

Human fetal breathing: associated changes in heart rate and beat-to-beat variability.

A computerized quantification of fetal heart rate and beat-to-beat variability was performed during and between fetal breathing episodes. Sixteen healthy pregnant women at term participated in the study. The results indicate that fetal breathing is associated with a significant increase in beat-to-beat variability (from 4.48 +/- 1.66 between breathing episodes to 5.80 +/- 2.04 during breathing episodes, p less than 0.01) and a small but significant decrease in fetal heart rate (from 142.7 +/- 8.6 bpm between breathing episodes to 140.4 +/- 8.6 bpm during breathing episodes, p less than 0.05).

Female↗