ABSTRACT
A simplified method of estimating fetal weight was developed and tested on 366 ultrasound examinations performed close to delivery. Constructed by linear regression on the sum of the biparietal diameter (BPD), mean abdominal diameter, and femur length against the logarithm of birth weight, the model was compared to the Shepard-Warsof model, which uses BPD and abdominal circumference to estimate fetal weight. Models using the same simplified approach to estimate fetal weight using BPD with mean abdominal diameter, and femur length with mean abdominal diameter, were also developed. Fetal weight estimate tables for these models involve only one variable, making them easier to use.
Subject(s)
Body Weight , Prenatal Diagnosis/methods , Ultrasonography/methods , Body Height , Body Surface Area , Female , Humans , Models, Biological , Pregnancy , Regression AnalysisABSTRACT
An assay has been developed to distinguish active from passive Rh0(D) immunization in a patient who had recently received hyperimmune anti-Rh0(D) immunoglobulin therapy. Isolated peripheral B lymphocytes from a pregnant woman at 32 weeks gestation were co-cultured with Epstein-Barr virus in a liquid growth medium. After 7 days, anti-Rh0(D) antibodies produced in vitro by the transformed lymphocytes were detected in culture supernatants, thereby proving active immunization and indicating the potential of hemolytic disease of the newborn in the current pregnancy. This assay was also performed with peripheral B lymphocytes from three groups of individuals: mothers known to be Rh0(D) immunized and who recently delivered Rh-positive infants, women with longstanding Rh0(D) immunization, and women who were treated with anti-Rh0(D) globulin. In the first group, anti-Rh0(D) antibodies were again detected after in vitro viral stimulation. In the latter two groups, essentially no anti-Rh0(D) activity was detected.
Subject(s)
Erythroblastosis, Fetal/diagnosis , Isoantibodies/analysis , Rh-Hr Blood-Group System , Adult , Antibody-Producing Cells/immunology , Erythroblastosis, Fetal/immunology , Female , Herpesvirus 4, Human , Humans , Immunization, Passive , PregnancyABSTRACT
A custom-built computer system combined with a commercial real-time ultrasonic scanner was used to predict fetal weight. A special three-dimensional (3D) locating system provided 3D coordinates of fetal surface points imaged on multiple ultrasound scans. The 3D coordinates were used to develop length and volume variables that are not available with commercial instruments. Multiple regressions were used to compare these lengths and volumes with more conventional diameters and circumferences for their ability to predict fetal weight. Measurements were made on 41 live fetuses within 48 hours prior to delivery (weight range 1,985-4,734 g, mean weight 3,421 g). Combinations of 19 measured variables were analyzed against birth weight and the natural log of birth weight. The correlation between log birth weight and combinations including lengths from 3D measurements was R = .93, SE = 73 g/kg. When volumes from 3D measurements (which are much more difficult to obtain) were added, the correlation was R = .94, SE = 69 g/kg. These results suggest that lengths from 3D measurements have the potential to improve fetal weight prediction by 25-30 per cent over current methods, which have an approximate error of 100 g/kg. The relative lack of improvement with volumes from 3D measurements is probably the result of technical problems which may be overcome with further research.
Subject(s)
Body Weight , Fetus/anatomy & histology , Ultrasonics , Birth Weight , Body Height , Computers , Female , Humans , Infant, Newborn , PregnancyABSTRACT
Routine ultrasound examination at 30 weeks gestation revealed an intrapulmonary cystic mass in an otherwise normal fetus. Following delivery at term, the diagnosis of congenital cystic adenomatoid malformation of the right lung was confirmed, and an elective right middle lobectomy successfully performed at nine days of age.
Subject(s)
Lung/abnormalities , Prenatal Diagnosis/methods , Ultrasonography , Adolescent , Diagnosis, Differential , Female , Humans , Infant, Newborn , PregnancyABSTRACT
The theoretical usefulness of volume as a predictor of fetal weight was assessed on 25 dead neonates with weight ranges between 364 and 3,650 gm. The correlation between volume, measured by water displacement, and weight was r = 0.999, with a standard error of 37 gm. A method is described for using volume, calculated from three-dimensional ultrasonic head and trunk reconstructions, to predict fetal weight. For the dead neonates, the correlation between measured weight and calculated head plus trunk volume was r = 0.985, with a standard error of 190 gm. The regression coefficient was 1.73, thus indicating that head and trunk volumes underestimate weight, as might be expected since limbs were not included. We conclude from this "ideal" situation that volume measurements will eventually provide the best estimates of fetal weight, and that three-dimensional head trunk reconstructions are reasonably accurate measures of overall volume.
Subject(s)
Body Weight , Fetus/physiology , Ultrasonography , Cephalometry , Humans , Prenatal DiagnosisSubject(s)
Ultrasonics/instrumentation , Biophysical Phenomena , Biophysics , Computers , Evaluation Studies as Topic , Humans , UltrasonographyABSTRACT
Ultrasonic measurements were made on 65 fetuses within 48 hours of delivery. Multiple regression analysis of birth weight and the natural logarithm of birth weight against several measured variables were obtained. The formula giving the best correlation was a polynomial regression of the natural logarithm of birth weight vs. trunk circumference, circumference, and a long axis measurement. The correlation was improved by excluding the first 15 patients but was not improved further by excluding the next 15. The best correlation was 0.944, giving a predicted birth weight error of +/- 103 Gm. (1 S.D.).
Subject(s)
Body Weight , Fetal Monitoring/methods , Fetus/physiology , Ultrasonography , Birth Weight , Evaluation Studies as Topic , Female , Humans , Pregnancy , Regression AnalysisABSTRACT
In this paper a method is described for obtaining and characterizing fetal blood velocity waveforms. The signals were recorded with a range-gated Doppler instrument and characterized after spectral analysis. Preliminary observations indicate differences in the waveforms obtained during normal pregnancies compared with some complicated pregnancies.
Subject(s)
Blood Flow Velocity , Fetus/physiology , Ultrasonography , Female , Humans , Pregnancy , Pregnancy Complications/physiopathologyABSTRACT
Qualitative doppler shift ultrasound estimations of blood velocity were made from umbilical arteries of 17 neonates for 90 sec after delivery using a 10 MHz doppler instrument. The mean maximum doppler shift frequency at 10 sec was 1.5 kHz +/- 0.3 (SE) reducing to 0.5 +/- 0.1 kHz at 60 sec after delivery. This indicates that flow velocity cannot be quantified. The initial mean pulsatility index was 10.6 suggesting that either constrictions were occurring in the arteries by 10 sec after delivery or that the placenta has a high impedance or both.
Subject(s)
Infant, Newborn , Ultrasonography , Umbilical Arteries/physiology , Blood Flow Velocity , Doppler Effect , Female , Humans , Pregnancy , Rheology , Ultrasonics/instrumentationABSTRACT
A local thermal dilution technique was used to estimate blood flow in the human umbilical vein during the first minute after delivery of the neonate. Estimates of flow were attempted at 101 deliveries and thermal dilution curves obtained at 52. The mean estimation of all flows recorded up to 20 seconds after delivery was 171 ml. per minute reducing to 58 ml. per minute between 40 and 60 seconds.
Subject(s)
Delivery, Obstetric , Umbilical Veins/physiology , Delivery, Obstetric/methods , Female , Humans , Infant, Newborn , Pregnancy , Regional Blood Flow , ThermodilutionABSTRACT
Human umbilical vein and artery diameters reduce significantly during the first 2 min after delivery, whereas blood gas tensions do not change significantly. Gas tension changes, therefore, cannot account for the reduction in the umbilical vessel diameters which occurs during this time.
